Lake Mahega: a mesothermic, sulphato-chloride lake in western Uganda

In May, 1971, Lake Mahega had pronounced mesothermy (40.W C at one metre). Solar heating of a bloom of baeteria and the blue-green alga, Synechococcus bacillaris Butch., probably caused the high temperature. A total ionic concentration gradient increasing from 192,600 mg 1itre-1 at the surface to 415,200 mg•litre- 1 at three metres stabilized the thermally inverted water. Nearly equal amounts of chloride and sulphate accounted for about 90% of the anionic composition. Sodium was the major cation. Crystals or the triple salt, northupite (Na2 CO3. MgCO3. NaCl) and of thenardite (Na2SO4) were mixed with the surface sediment. We believe it is possible that primary northupite depnsition is occurring. Lake Mahega is also the first mesothermic, sulphato-chloride lake reported for East Africa.

Aerodynamic effects in ink-jet printing on a moving web

The airflow between the fast-moving substrate and stationary print heads in a web print press may cause print quality issues in high-speed, roll-to-roll printing applications. We have studied the interactions between ink drops and the airflow in the gap between the printhead and substrate, by using an experimental flow channel and high-speed imaging. The results show: 1) the gap airflow is well approximated by a standard Couette flow profile; 2) the effect of gap airflow on the flight paths of main drops and satellites is negligible; and 3) the interaction between the gap airflow and the wakes from the printed ink drops should be investigated as the primary source of aerodynamically- related print quality issues. ©2012 Society for Imaging Science and Technology.

生长激素及其基因转移对鱼类生长和渗透压的调节作用

生长激素及其基因转移对鱼类生长和渗透压的调节起着重要作用。转生长激素基因鱼表现出明显的快速生长效应。生长激素促进了鲑科鱼类对海水的适应能力。本文对此进行了综述 ,并讨论了生长激素及其基因转移对鱼类生长和渗透压调节作用的生理机制、生长激素与胰岛素样生长因子以及甲状腺激素的关系

鸭儿湖地区多氯代二苯并二/呋喃(PCDD/F)的污染状况及其来源归宿的初步研究

对鸭儿湖地区的底泥和土壤样品中的多氯代二苯并二／呋喃（ＰＣＤＤ／Ｆ）的污染状况进行了研究．结果表明，鸭儿湖部分地区已被ＰＣＤＤ／Ｆ严重污染，该类污染物来源于附近某化工厂排放的化工废水，其中，ＰＣＤＤ／Ｆ主要以高氯取代的ＨｐＣＤＤｓ和ＯＣＤＤ为主，总结我们的已有实验结果，鸭儿湖１号氧化塘中高残留的ＰＣＤＤ／Ｆ如果控制不当将会转移扩散，可能造成对周围环境的进一步污染．

白暨豚血红蛋白电泳的相对迁移率

<正> 白暨豚血红蛋白的电泳图谱有清晰的两条带。它们的相对迁移率(mr)分别是0.415和0.485;相对迁移率的百分比(mr％)分别是84.70％和99.07％(人类Hb A mr％=100％)。较慢带含量的百分比是68.42％,较快带的为31.58％。按照蒙蒂(De Monte)和皮莱里(Pilleri)的命名法,白暨豚的血红蛋白类型应在Ⅴ和Ⅵ之间。在血红蛋白溶液中没发现非血红素蛋白带NHP(non-hem protein)。

Xenobiotics removal from polluted water by a multifunctional constructed wetland

Removal efficiencies on xenobiotics from polluted water in a twin-shaped constructed wetland consisting of a vertical flow chamber with the crop plant Colocasia esculenta L. Schott and a reverse vertical flow one with Ischaemum aristatum var. glaucum Honda, were assessed by chemical analysis and bioassays. After a four-month period of application, removal efficiencies of the applied pesticides parathion and omethoate were 100%, with no detectable parathion and omethoate in the effluent. For the applied herbicides, the decontamination was less efficient with removal efficiencies of 36% and 0% for 4-chloro-2-methyl-phenoxyacetic acid and dicamba, respectively. As shown by toxicity assay with duckweed Lemna minor L., growth retardation may occur if the water treated for herbicide removal is used in irrigation of sensitive cultivars in agriculture or horticulture. In contrast to I. aristatum var. glaucum Honda, the crop C esculenta L. Schott has a high yield in biomass production as a valuable source of renewable energy. (C) 2002 Elsevier Science Ltd. All rights reserved.

The precocious Chinese mitten crab: Changes of gonad, survival rate, and life span in a freshwater lake

Changes of the gonad. survival rate, and life span of the precocious (i.e., sexually mature in their first October-November, at the age of 5 or 6 months) Chinese mitten crab (Eriocheir sinensis) were studied in a small, shallow, macrophytic, freshwater lake along the middle reaches of the Changjiang River, China. The gonosomatic index (GSI) reached peak during the next March when the female GSI was 12.32 +/- 1.75 SD% and the male GSI A as 4.24 +/- 0.19%. The sexual glands degraded from then on. In the first ten-day period of the following July, there was no complete ovum in the ovary. and the sperm became thin and lost adhesion. The population declined sharply from November to July, and the last one (a female) died in the middle of July, which indicated that the life span of the precocious crab was about 12 months (from larval hatching in June to death in July of next year). The survival curve might be expressed as Y = 1.09exp(-0.018x) (Y survival rate; x: days) for the precocious crabs stocked in experimental cages.