甲醛溶液对发头裸腹溞及其体表聚缩虫影响的试验

不同浓度的甲醛溶液对枝角类发头裸腹溞Moinairrasa的致毒效应以及对其体表附着的聚缩虫Zoothamniumsp．的杀灭效果的试验结果表明，12h、24h两个作用时段中，甲醛浓度与发头探腹溞相对存活率之间以及甲醇浓度与发头裸腹溞表聚缩虫营养体脱落率之间存在一定的函数关系．在确立上述函数基础上，可得出控制聚缩虫感染的两种有效方法：①在保证溞存活率不低于66％的情况下，选用最低有效浓度（19．mg／kg）的甲醛溶液作用24h可杀灭100％聚缩虫；②在保持溞存活率较高（70％－90％）的情况下，选用相应浓度的甲醛液作用24h杀灭87％－29％聚缩虫，并辅以更换新水等措施，也可将聚缩虫感染的危害控制在一定的范围内．     

陕西几次历史地震震中位置的匡定

本文对《陕西省志.地震志》、《中国地震历史资料汇编》(第一卷)有关陕西几次历史地震震中位置作了匡定。认为公元前32年(汉成帝建始元年九月)发生的地震,原定震中在绥德东南25千米不确,应在榆林市东南30千米的王沙坬村。对公元477年6月(北魏孝文帝太和元年五月)发生在统万镇的地震,指出参考震中既不在横山北,也非内蒙古乌审旗南,而是在陕西省靖边县东北的红墩界乡。对公元1650年9月(清世祖顺治七年八月)和公元1813年7月(清仁宗嘉庆十八年六月)两次地震的参考震中,指出安定现属子长县。     

藏北申扎、班戈地区奥陶纪和志留纪的一些头足类化石

文内描述的头足类化石采自藏北申扎县柯耳多组和班戈县东卡组,这些头足类化石分别属于塔飞角石目薇角石科、珠角石目链角石科以及肿角石目约维兰角石科。其中约维兰角石科分子系首次在藏北发现。笔者认为柯耳多组的时代属于中奥陶世,东卡组的时代当属于早至中志留世。 由于中奥陶世Sinoceras以及早至中志留世约维兰角石科分子在藏北的发现,表明西藏海域与华中—西南区浅海从中奥陶世到中志留世时都是相通连的。     

边眼虫属在新疆西准噶尔地区的发现

在新疆西准噶尔地区塔尔巴哈台山首次发现边眼虫属的一个新种,定名为Plagiolariaeminensis Guo (Sp.nov.).化石产于中泥盆统库鲁木迪组下部.     

Isolation and characterization of phenanthrene-degrading strain Sphingomonas sp. GY2B

Polycyclic aromatic hydrocarbons （PAHs） are of great concern since most of them have been shown to be toxic, mutagenic, and carcinogenic. Bioremediation, based on certain species of microorganisms, is regarded as an alternative method to detoxify or remove PAHs from the contaminated sites. Phenanthrene has been often used as a model substance for microbial metabolism of ＂bay-region＂ and ＂K-region＂ containing carcinogenic PAH. The focus of the present study is to isolate and identify microorganisms which could use phenanthrene as the sole carbon and energy source. Such microorganisms are expected to be of interest as a source organism for the bioremediation of PAHs polluted soils. The bacterial consortia were enriched from PAH contaminated soils with water-silicon oil biphasic systems. An aerobic bacterial strain efficiently utilizing phenanthrene as the sole carbon and energy source was isolated from bacterial consortia GY2 and identified as Sphingomonas sp. strain GY2B. Strain GY2B was susceptible to some common used antibiotics such as cefuroxime, chloramphenicol, erythromycin and tetracycline and intermediate susceptible to amoxycillin. Moreover, no plasmids could be isolated from strain GY2B using the standard alkaline-SDS method. At pH 7.4 and 30℃ strain GY2B had an optimal growth condition and in this condition above 99.8% phenanthrene was degraded under initial concentration of 100 mg/L. The addition of low concentration of glucose （10-200 mg/L） in MSM containing 100 mg/L phenanthrene could enhance the growth of strain GY2B, while the high concentration of glucose （〉500 mg/L） could exert an inhibitive effect on cell growth. Besides phenanthrene, strain GY2B could also use naphthalene, phenol, 1-hydroxy-2-naphthoic acid, 2-naphthol, salicylic acid and catechol as the sole carbon and energy source. The growth of strain GY2B on salicylic acid and catechol showed that the degradation of phenanthrene might follow salicylate pathway.     

Predation of the beetle Rhantus sikkimensis (Coleoptera: Dytiscidae) on the larvae of Chironomus Meigen (Diptera: Chironomidae) of the Darjeeling Himalayas of India

The dytiscid beetle Rhantus sikkimensis, Regimbart, 1899 (Coleoptera: Dytiscidae), a member of the freshwater insect communities of the Darjeeling Himalayas, were noted to predate on the coexisting larvae of Chironomus sp. Meigen. Evaluation of predation by R. sikkimensis on Chironomus sp. larvae, in the laboratory, revealed that a single adult morph of R. sikkimensis could kill and consume on an average 10–90 and 10–78 numbers of small and large Chironomus sp. larvae, respectively, per day, depending on the prey density. The attack rate ranged between 520 and 537, and the handling time ranged between 4.3 and 8.6 depending on the size of the preys. The predation varied with respect to predator density also, with a maximum of 151 larvae killed by three predators per day. Two indices of predation, ingestion rate (IR) ranging between 13.33 and 74.15 larvae/day/predator and clearance rate (CR) ranging between 19.67 and 39.99 L prey/day/predator, varied with the prey size and predator density, significantly, when the predation was observed for 9 consecutive days, at two predator densities. It was also noted that R. sikkimensis predated on an average 9.8 larvae of Chironomus sp. and 1 larva of Culex sp., when the larvae of both the species are present together as preys, showing a preference for the Chironomus sp. larvae.     

Fossil findings from the Sıcak Çermik fissure ridge-type travertines and possible hominid tracks,Sivas, Central Turkey

S?cak Çermik (Sivas) is an important geothermal and recent travertine formation area in Central Anatolia. The majority of travertines found in the region comprise fissure-ridge type travertines according to morphological classification. At the location called Tepe Çermik within the travertine area, fill containing fossil bone fragments of Equus sp., Bovidae and other abundant animals formed within the fracture axis of a N–S striking fissure-ridge travertine developed under control of tectonic forces. The finds of these fossils in fissure-ridge travertines linked to tectonic forces indicates formation of a unique fossil environment created under the control of these forces. The Accelerator Mass Spectrometry Radiocarbon Dating analyses of fossils from the study area determined the fills were older than 43,000 years. The U/Th age of a sample from the most recently-formed banded travertine in the axis of the fracture was identified as 278,540 ± 18,436 years. As a result, the ages of fossils found within this fill are thought to be between 43,000 and 278,540 ± 18,436 years old. The high amount of perissodactyla and artiodactyla fossils found within fill in the axis of the fissure-ridge travertine probably indicates the presence of hominids who chose the region for hunting or settlement. The Equus sp. and Bovidae fossil samples found in the axis of the fracture indicate that in the dry and cold glacial period the paleogeography in a large portion of Anatolia comprised desert-like steppe.     

颤藻对6种抗生素敏感性的研究

蓝藻是一种原核藻类,其结构和遗传复杂性同革兰氏阴性菌相似,具有独立的遗传结构—质粒和天然的转化和重组系统,所以蓝藻不仅是植物光合作用、叶绿体起源和植物进化研究的理想材料,还可能成为高等植物基因表达的重要宿主[1]。     

混合藻类高光谱特征及其叶绿素a分离定量模型

利用地物高光谱遥感技术,在室内进行小球藻、聚球藻及其混合藻高光谱测量.得到这3组藻的反射光谱特征,同时进行叶绿素a(Chl.a)浓度测量.利用Matlab软件中的神经网络工具箱对得到的高光谱数据进行了曲线拟合.并用拟合结果和光谱测量实际结果分别建立了两种单一藻类的定量模型单一小球藻Chl.a最优的定量模型为用反射率实际值建立的小球藻单波段反射率模型Chl.a=1×10~7(R_(687))~2-37016R_(687)+53.64.单一聚球藻Chl.a最优的定量模型为利用反射率实际值建立的聚球藻两波段模型Chl.a=853 15×[R~(-1)(669)-R~(-1)(730)]×R(730)+505.78.在对两种单一藻类定量模型研究的基础上分别用单波段反射率分离模型、三波段分离模型和两波段分离模型对由小球藻和聚球藻组成的混合藻进行了Chl.a浓度分离.其中单波段反射率分离模型和两波段分离模型得到了较好的分离结果,单波段反射率分离模型结果要优于两波段分离模型结果.利用神经网络模型拟合值构建的模型要优于直接用反射率测量值构建的模型,而三波段分离模型的分离结果不理想,不适用于本研究.     

Scum in Activated Sludge Plants: Impact of Non‐filamentous and Filamentous Bacteria

Excessive scum production is a widespread phenomenon in present activated sludge wastewater treatment. The question how foaming is initiated and stabilized is still unanswered. Hydrophobic wastewater ingredients and surface active material such as synthetic surfactants are discussed among others as major causative agents for scum production. Focusing on biological impacts non‐filamentous bacteria isolated from scum turned out to contribute to flotation by both cell surface hydrophobicity and emulsification activity, depending on the prevailing substrate and milieu conditions. The biological characterization of scum based on microscopic sludge investigation of conspicuous microorganisms resulted in a significant shift of filamentous and non‐filamentous organism populations with Gram‐positive bacteria prevailing in present nutrient removal plants as compared to the situation ten years ago. Their hydrophobic cell surface is supposed to support adherence and stabilization of interfaces and thus promote sludge flotation. In scum six types of filamentous bacteria turned out to be numerous: Microthrix parvicella and nocardioform actinomycetes, both of them being enriched in the scum fraction, moreover Nostocoida limicola and Eikelboom types 0041/0675, 1851, and 0092. Possible interactive mechanisms between non‐filamentous and filamentous scum bacteria and their selection factors are discussed in order to contribute to a better understanding of scum formation and to provide efficient troubleshooting measures.