Hg concentrations and accumulations in fungal fruiting bodies, as influenced by forest soil substrates and moss carpets

This article summarizes trends in total Hg concentrations (THg) in fungal fruiting bodies (basidiomata) and their underlying soil substrates in the absence and presence of surrounding moss layers. Three forest locations across south-western New Brunswick spanning from a central mainland location to Grand Manan Island in the Bay of Fundy were chosen for the study. Geographic location had an effect on THg in the soil layers and in the basidiomata (THg on island > THg along the mainland coast > THg mainland) but this effect was weak and probably obscured by the large THg variations within the basidiomata and their soil and moss substrates at each location. Within the soil, THg increased with increasing total organic S (TS) and C (TC) concentrations, and depended on type of moss cover if present. Within the mosses, THg varied by species, by moss-internal TS, and by THg and TS within the underlying soil. Basidiomatal THg also varied strongly by species, and was further affected by: (i) developmental stage, from emergence to senescence, (ii) cap versus stalk, (iii) basidiomatal TS, and (iv) soil THg, TS and TC. These variations and their interdependencies were explored and quantified by way of multiple regression analyses. Basidiomatal bioconcentration of soil THg (F layer) varied strongly by species as well. Basidiomatal Hg extraction from the soil was estimated to be small in terms of reducing the accumulated Hg loads within the soil, but represents a re-entry point of Hg into the local food chain.     

Two phase modal analysis of nonlinear sloshing in a rectangular container

Sloshing, or liquid free surface oscillation, in containers has many important applications in a variety of engineering fields. The modal method can be used to solve linear sloshing problems and is the most efficient reduced order method that has been used during the previous decade. In the present article, the modal method is used to solve a nonlinear sloshing problem. The method is based on a potential flow solution that implements a two-phase analysis on sloshing in a rectangular container. According to this method, the solution to the mass conservation equation, with a nonpenetration condition at the tank walls, results in velocity potential expansion; this is similar to the mode shapes used in modal method. The kinematic and dynamic boundary conditions create a set of two-space-dimensional differential equations with respect to time. The numerical solution of this set of differential equations, in the time domain, predicts the time response of interfacial oscillations. Modal method solutions for the time response of container sloshing due to lateral harmonic oscillations show a good agreement with experimental and numerical results reported in the literature.     

Kinetic and equilibrium study of Ni(II) sorption from aqueous solutions onto Peganum harmala-L

In this study, the adsorption behavior of Ni(II) in an aqueous solution system using natural adsorbent Peganum harmala-L was measured via batch mode. The prepared sorbent was characterized by scanning electron microscope, Fourier transform infrared spectroscopy, N₂ adsorption–desorption and pH_zpc. Adsorption experiments were carried out by varying several conditions such as contact time, metal ion concentration and pH to assess kinetic and equilibrium parameters. The equilibrium data were analyzed based on the Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherms. Kinetic data were analyzed using the pseudo-first-order, pseudo-second-order and intra-particular diffusion models. Experimental data showed that at contact time 60 min, metal ion concentration 50 mg/L and pH 6, a maximum amount of Ni(II) ions can be removed. The experimental data were best described by the Langmuir isotherm model as is evident from the high R ² value of 0.988. The adsorption capacity (q _m) obtained was 68.02 mg/g at an initial pH of 6 and a temperature of 25 °C. Kinetic studies of the adsorption showed that equilibrium was reached within 60 min of contact and the adsorption process followed the pseudo-first-order model. The obtained results show that P. harmala-L can be used as an effective and a natural low-cost adsorbent for the removal of Ni(II) from aqueous solutions.     

Flood frequency analysis based on simulated peak discharges

Flood frequency approaches vary from statistical methods, directly applied on the observed annual maximum flood series, to adopting rainfall–runoff simulation models that transform design rainfalls to flood discharges. Reliance on statistical flood frequency analysis depends on several factors such as the selected probability distribution function, estimation of the function parameters, possible outliers, and length of the observed flood series. Through adopting the simulation approach in this paper, watershed-average rainfalls of various occurrence probabilities were transformed into the corresponding peak discharges using a calibrated hydrological model. A Monte Carlo scheme was employed to consider the uncertainties involved in rainfall spatial patterns and antecedent soil moisture condition (AMC). For any given rainfall depth, realizations of rainfall spatial distribution and AMC conditions were entered as inputs to the model. Then, floods of different return periods were simulated by transforming rainfall to runoff. The approach was applied to Tangrah watershed in northeastern Iran. It was deduced that the spatial rainfall distribution and the AMCs exerted a varying influence on the peak discharge of different return periods. Comparing the results of the simulation approach with those of the statistical frequency analysis revealed that, for a given return period, flood quantiles based on the observed series were greater than the corresponding simulated discharges. It is also worthy to note that existence of outliers and the selection of the statistical distribution function has a major effect in increasing the differences between the results of the two approaches.     

渤海西岸暴雨中尺度对流系统的结构及成因

利用卫星、雷达和加密自动站等监测资料,结合VDRAS系统资料和1°×1° NCEP再分析资料,对造成黑昼和暴雨的中尺度对流系统的空间、热动力结构特征和发生、发展及维持原因进行了分析。结果表明:2004—2009年渤海西岸圆形α-中尺度对流系统有别于南方,其中只有16%可发展为中尺度复合体;黑昼现象是影响系统的特殊性所致。突发性暴雨的制造者是α-中尺度对流系统西端不断新生的β-中尺度对流系统,其发生、发展、维持与边界层内冷池外流、对流层低层 (1.3~2.4 km) 侵入的西北气流与西南气流形成的辐合线或交汇线有密切关系。α-中尺度对流系统的上升速度中心在500 hPa附近,多个β-中尺度对流系统分别具有独自的垂直气流和弱边界层环流。α-中尺度对流系统内部扰动温度呈下负上正的垂直分布,促使了不稳定层结趋于稳定;冷池呈东厚西薄的楔形结构,有利于β-中尺度对流系统发展维持。     

Decolorization of different azo dyes by Phanerochaete chrysosporium RP78 under optimal condition

Detoxification of synthetic dyes is one of the main challenges in clearing textile industry wastes. Biodegradation of azo-dyes using Phanerochaete chrysosporium is one the most environmentally friendly methods available. The main enzymes responsible for mycodecolorization process are lignin and manganese peroxidases. Here, optimization of expression conditions has been carried out with manipulating culture condition and nutrient sources. Therefore, the effects of buffer and temperature as well as nitrogen source on lignin peroxidase and manganese peroxidase production were investigated at two levels and four levels, respectively. For this purpose, P. chrysosporium RP78 based on Taguchi design of experiment has been applied. Maximum lignin and manganese peroxidase activities of 182 ± 2.5 U/L and 850 ± 41 U/L were obtained under predicted optimum conditions, respectively. Thereby, about 100 % decolorization was achieved after 24 h for two most widely used groups of azo dyes in textile industry consisting reactive and acidic. The physical adsorption of the azo dyes by mycelia was not significant which indicated that the enzymatic degradation of the dyes was occurred. Time profile of these enzymes showed that manganese peroxidase was peaked on 9^th day while lignin peroxidase peaked on 13^th day and remained stable in the culture. The extracellular expression profiles of both were studied by 2 dimensional gel electrophoresis to partially characterize the enzymes.     

Cyanopolyyne chemistry in TMC-1

Using pseudo-time-dependent models and three different reaction networks, a detailed study of the dominant reaction pathways for the formation of cyanopolyynes and their abundances in TMC-1 is presented. The analysis of the chemical reactions show that for the formation of cyanopolyynes there are two major chemical regimes. First, early times of less than ～10⁴ yrs when ion-molecule reactions are dominant, the main chemical route for the formation of larger cyanopolyynes is $$C_n H^ + \xrightarrow{N}C_n N^ + \xrightarrow{{H_2 }}HC_n N^ + \xrightarrow{{H_2 }}H_2 C_n N^ + \xrightarrow{{e^ - }}HC_n N$$ wheren=5, 7, and 9. Second, at times greater than 10⁴ yrs, when neutral-neutral reactions become dominant, two major reaction routes for the formation of cyanopolyynes are (a), $$HCN\xrightarrow{{C_2 H}}HC_3 N\xrightarrow{{C_2 H}}HC_5 N\xrightarrow{{C_2 H}}HC_7 N\xrightarrow{{C_2 H}}HC_9 N$$ and (b) $$C_n H_2 + CN \to HC_{n + 1} N + H,{\text{ }}n = 4,6, and 8$$ depending on the reaction network used. The results indicate that for route (a) large abundances ofC ₂ H (fractional abundances of ～10^?7), and for route (b) large abundances ofC ₂ H ₂ are required in order to reproduce the observed abundances of cyanopolyynes. The calculated abundances of cyanopolyynes show great sensitivity to the value of extinction particularly att?5×10⁵ yrs (i.e. photochemical timescale). The effect of other physical parameters, such as the cosmic-ray ionization abundances are also examined. In general, the model calculations show that the observed abundances of cyanopolyynes can be achieved by pseudo-time-dependent models at late times of several million years.     

一种高效的城市部件普查方法

数字化城市管理是经济建设及信息化发展的迫切需求,城市部件普查是将物化的城市管理对象转化成数字化的管理信息,是数字化城市管理的基础。以威海市城市部件普查项目为例,通过分析城市部件的普查需求,采用GPS-RTK测量与移动设备调绘相结合的数据采集方法,以及"粗确权"、"分类别"、"分区域"的部件属性信息调查方法,构建相应的城市部件普查技术体系。基于该体系进行图形数据与属性信息的城管数据库搭建,构建一种高效城市部件普查技术方法。     

SVD分析揭示的澳大利亚高压年际变化对中国夏季降水的可能影响

澳大利亚高压是东亚夏季风系统的重要成员之一,其对中国夏季气候存在显著影响.为了进一步弄清年际时间尺度上的澳大利亚高压变化对中国东部夏季降水的影响,利用澳大利哑海平面气压和中国夏季降水站点资料,使用SVD和线性回归方法揭示了澳大利亚高压的年际变化与中国夏季降水异常的联系,得到:SVD的第1模态的时间系数与通常使用的澳大利亚高压指数相关可达到0.98.在有无考虑ENSO的影响时,SVD的第1模态均反映出澳大利亚高压的年际变化与中国江南地区夏季降水存在密切联系,也即澳大利亚高压增强(减弱)时,江南地区降水增多(减少).澳大利亚高压对中国夏季降水的可能影响途径为:澳大利哑高压通过影响赤道纬向气流和越赤道气流并通过类似PJ波列的方式影响到中国东部地区:澳大利亚高压增强时,造成西太平洋副热带高压偏南、偏西,同时,105°E处越赤道气流显著加强,为江南地区提供充足水汽源,利于中国江南地区降水;澳大利亚高压减弱时,情况相反;在强(弱)澳大利哑高压年,印度尼西亚及热带辐合带海区SSTA负(正)异常使得低层风场的异常辐散(辐合),激发了澳大利哑南部以及西太平洋地区异常反气旋(气旋)环流,同时江南地区出现异常辐合(辐散),引起大气异常上升(下沉)运动,有利于中国江南地区夏季降水异常偏多(偏少).