Exploratory fishing experiments in Hirakud reservoir - Orissa State (1967-70)

Suitable areas for fishing have been located in the middle and upper regions of the Mahanadi course of Hirakud reservoir. In the former the suitable period is during summer and beginning of monsoons, and in the latter in summer and winter months. The fishery of the reservoir is contributed by four species namely S. silondia, L. fimbriatus, C. mirgala and C. catla.

草鱼仔鱼耳石的自然标记和生长轮的清晰度

将野生和人工繁殖的草鱼仔鱼的耳石取出并置于显微镜下观察微结构特征。结果表明 :草鱼耳石一般有一个圆形或卵圆形的原基和中心核 ,但有 0 4 1%～ 4 6 7%的样本具有双原基或双中心核。343尾野生仔鱼中 ,6 71%的个体在矢耳石和微耳石上具有营养转换标记 ,而 187尾人工繁殖的仔鱼中 ,在矢耳石和微耳石上出现营养转换标记的比例分别是 6 4 17%和 5 0 80 % ;在营养转换标记处 ,矢耳石和微耳石的直径分别为 5 4 12±9 4 9μm和 4 0 4 8± 7 0 2 μm (n =5

The first study on the effects of microcystin-RR on gene expression profiles of antioxidant enzymes and heat shock protein-70 in Synechocystis sp PCC6803

Microcystins are heptapeptide toxins produced by cyanobacteria. Microcystin-RR(MC-RR) is a common variant among the 80 variants identified so far. There have been many investigations documenting the toxic effects of microcystins on animals and higher plants, but little is known on the toxic effects of microcystins on algae, especially at molecular level. We studied the effects of MC-RR on gene expression profile of a few antioxidant enzymes and heat shock protein-70 (Hsp70) in Synechocystis sp. PCC6803. After two days post-exposure, a high dose toxin (5 mg/l, about 4.8 x 10(-3) mM) significantly increased expression levels of the genes gpx1, sodB, katG, acnB, gamma-TMTand dnaK2, while a relatively low dose toxin (1 mg/l, about 9.63 x 10(-4) mM) induced a moderate and slow increase of gene expression. Our results indicate that MC-RR could induce the oxidative stress in Synechocystis sp. PCC6803 and the increase in gene expression of antioxidant enzymes and Hsp70 might protect the organism from the oxidative damage. in addition, cell aggregation was observed during the early period of exposure, which might be a specific oxidative stress reaction to MC-RR. (C) 2008 Elsevier Ltd. All rights reserved.

Radar interferometer measurements of space debris using the Evpatoria RT-70 transmitter

The ability of the Evpatoria RT-70 radar complex to perform research on space debris was investigated in four trial experiments during 2001-2003. The echo-signals of 25 objects at geostationary, highly elliptical and medium-altitude orbits were recorded on magnetic tapes at radio telescopes in Russia, Italy, China and Poland. The multi-antenna system configuration gives potential to supplement the classic radar data with precise angular observations using the technique of Very Long Baseline Interferometry. The first stage of such processing was fulfilled by the correlator in N. Novgorod, Russia. The cross-correlation of transmitted and received signals was obtained for the 11 objects on the Evpatoria-Bear Lakes, Evpatoria-Urumqi and Evpatoria-Noto baselines. This activity also promoted developing the optical observations of geostationary objects, conducted for the improvement of the radar target ephemerides. (C) 2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

70年来陕西省纸坊沟流域农业生态经济系统耦合态势

"农业生态经济系统耦合"的研究与实践对于实现农业产业与资源相一致,建立持续、高效的农业生态经济系统具有重要的意义。耦合度可以阐明农业经济系统与农业生态系统互动关系,判定农业生态经济系统耦合态势。在分析陕西省纸坊沟流域农业生态经济系统耦合关系的基础上,参照系统科学等理论及相关研究结果建立了农业经济系统与农业生态系统耦合度模型,并计算和分析了该流域70a来的耦合度。结果表明,农业生态经济系统的耦合过程可以划分为4个阶段:Ⅰ.经济系统依赖生态资源进行原始化农业生产阶段;Ⅱ.农业生产掠夺式利用生态资源,生态系统供给能力不断减少阶段;Ⅲ.农业经济系统与生态系统协调化发展阶段;Ⅳ.降低农业发展速度,促使生态系统重建阶段。纸坊沟流域从1938～2008年先后经历了第Ⅰ阶段、第Ⅱ阶段和第Ⅲ阶段。目前处于第Ⅲ阶段,但在"系统发展"过程中已潜伏了越来越大的危机,到2018年系统耦合突破"协调"界限,"相悖态势"将明显表现出来。为此,纸坊沟流域必须调整产业布局,发展草畜产业,进行产业升级,优化产业结构,实现农业生态经济系统协调、持续发展。

旱地地膜和秸秆双元覆盖栽培下小麦产量与水分效应

通过覆盖措施提高水分利用率对旱地农业生产具有重要意义。该文采用田间对比试验,研究了旱地冬小麦几种覆盖栽培下产量、水分利用率、土壤水分剖面和硝态氮的分布的差异。结果表明,地膜和秸秆双元覆盖模式下小麦籽粒产量比对照增产12.11%～17.65%,水分利用效率(WUE)比常规栽培提高7.2%～30.8%,土壤0～20 cm土层的含水量提高到12%～16%,硝态氮含量提高到4.70～10.17 mg/kg。地膜和秸秆双元覆盖模式能够显著的提高作物产量和水分利用率,并显著增加耕层土壤中水分含量和硝态氮含量,减轻了土壤剖面硝态氮的淋溶累积。

钼体系催化合成1,2－聚丁二烯的研究

本工作通过较系统地研究Ziegler-Natta型钼催化体系对丁二烯聚合的催化作用，发现一类活性很高的钼催化剂。此类催化剂以无毒，资源丰富的加氢汽油为溶剂，活性已接近工业化的Ni、Co、Ti等体系。同时，本工作又找到了大幅度调节聚合物分子量和链结构的方法，发现了具有活性聚合特点的钼催化体系，初步考察了钼体系催化丁二烯聚合的动力学行为；并利用红外光谱，~(13)C-NRM、X-射线衍射和热分析等方法研究了所得聚合物的链结构和聚集态结构，对聚合物的基本性能也进行了初步考察，发现所得聚合物的一些基本性能超过天然橡胶。此类高活性钼催化剂由MoCl_4OR和(i-Bu)_2AlOAr组成，R为C_(8-18)烷基，Ar为芳基。本催化体系在70 ℃下催化丁二烯聚合时，催化剂用量为Mo/J摩尔比等于4 * 10~(-5)时，转化率可达78％。本体系聚合物分子量可用烯丙基卤等调节，其中烯丙基碘的效果最好。在Mo/J = 8 * 10~(-5)时，烯丙基碘/Mo摩尔比为0.1时即可使聚合物分子量下降约50万；烯丙基碘/Mo摩尔比为10时，聚合物重均分子量即小于20万（不加烯丙基碘为270万）。本体系聚合物分子量分布很窄，聚合温度为30 - 70 ℃时，_W/_n为1.5-2.0；_W/_n与聚合温度呈直线关系，利用外推法估计和动力学考察，本体系在－18 ℃左右有可能引发活性聚合。本体系聚丁二烯含有85％以上1,2－链节，其1，2-链节含量也可以用某些极性添加剂来调节。利用烯丙基碘做调节剂，可制得1,2－链节含量高达98％的聚丁二烯。烯丙基碘还可以调节聚合物链节的立体构型和序列分布；随着烯丙基碘用量的增加，间同1,2－链节增多，全同和无规1,2－链节减少，序列分布的有规性增加，链结构趋于规整。根据动力学初步研究结果，本体系催化丁二烯聚合的速度对单体浓度呈一级关系，表现活化能为17.07千卡／摩卡，催化剂利用率为4％，链增长速度常数为: k_(p30℃) = 40 (升／摩尔·分，下同), k_(p40℃) = 97, k_(p50℃) = 267, k_(p60℃) = 508, k_(p70℃) = 12077。本体系聚合物在烯丙基碘/Mo摩尔比小于2时，无论静态或拉伸下均为无定型；烯丙基碘/Mo摩尔比大于2而小于8时，静态下为无定型，而拉伸时产生结晶，与天然橡胶类似；烯丙基碘／Mo摩尔比大于8时，静态下亦有一定程度的结果。

低能He~(2+)与He原子碰撞转移电离出射电子能谱研究；Investigation on Electron Energy Spectra of Transfer Ionization Process in 70 and 100 keV He~(2+) Colliding on He

利用反应显微成像谱仪对70和100keV He2+与He原子碰撞转移电离(TI)过程中不同出射角度的电子能谱进行了测量,观测到出射电子能谱具有如下分布特征:出射电子速度分布介于0和入射离子速度vp之间;在不同出射角度电子能谱分布均有一极大值存在,随着出射角度的增大,能谱分布极大值逐渐减小;当电子出射角度等于45°时,多数电子集中在0eV附近。上述特征可由低能离子-原子碰撞"准分子"模型进行定性解释。在100keV He2+-He转移电离出射电子能谱中有靶电子被俘获至散射离子连续态(electron capture to continuum,简称ECC)电子的贡献,这可看做是动力学两步过程的作用。

Medium-spin states in Ge-70 and the role of the g(9/2) orbital

Medium-spin states of Ge-70 have been studied via the Ni-60(C-12,2p gamma)Ge-70 reaction at 45 MeV. The ground-state band and the second 0(+) band have been extended to the 12(+) and 8(+) states, respectively. Two negative-parity bands, one of which has a coupled structure and the other has a decoupled structure, have been observed additionally. Although the latter decoupled structure was known up to the (21(-)) state from a previous experiment, the part of the level scheme up to the 15(-) state has been largely modified by the present experiment. Backbendings observed in the positive- and negative-parity yrast bands have been compared with those of the neighboring even Ge isotopes. The experimental level structure has been compared with the shell-model calculations in the model space (2p(3/2), 1f(5/2), 2(p1/2), 1g(9/2)) employing two kinds of effective interactions, one of which is an extended P + QQ interaction with monopole interactions and the other is developed from a renormalized G matrix. Microscopic structures of the observed bands have been discussed with the help of the shell-model calculations.

Early Embryonic Exposure to Polychlorinated Biphenyls Disrupts Heat-Shock Protein 70 Cognate Expression in Zebrafish

Polychlorinated biphenyls (PCBs) are persistent environmental contaminants that have documented neurological effects in children exposed in utero. To better define neuronally linked molecular targets during early development, zebrafish embryos were exposed to Aroclor 1254, a mixture of PCB congeners that are common environmental contaminants. Microarray analysis of the zebrafish genome revealed consistent significant changes in 38 genes. Of these genes, 55% (21) are neuronally related. One gene that showed a consistent 50% reduction in expression in PCB-treated embryos was heat-shock protein 70 cognate (Hsc70). The reduction in Hsc70 expression was confirmed by real-time polymerase chain reaction (PCR), revealing a consistent 30% reduction in expression in PCB-treated embryos. Early embryonic exposure to PCBs also induced structural changes in the ventro-rostral cluster as detected by immunocytochemistry. In addition, there was a significant reduction in dorso-rostral neurite outgrowth emanating from the RoL1 cell cluster following PCB exposure. The serotonergic neurons in the developing diencephalon showed a 34% reduction in fluorescence when labeled with a serotonin antibody following PCB exposure, corresponding to a reduction in serotonin concentration in the neurons. The total size of the labeled neurons was not significantly different between treated and control embryos, indicating that the development of the neurons was not affected, only the production of serotonin within the neurons. The structural and biochemical changes in the developing central nervous system following early embryonic exposure to Aroclor 1254 may lead to alterations in the function of the affected regions.

科尔沁沙地70种草本植物个体和构件生物量比较研究

比较分析了科尔沁沙地70种草本植物盛花期时的个体和构件生物量特性。结果表明:43种植物个体生物量小于5.0 g,大部分物种根、茎、叶、花等构件的生物量均小于2.0 g,62种植物的根冠比小于1,说明70种草本植物中的大部分物种以地上生物量为主,只有少数物种具有较发达的地下根系。植物各构件生物量之间呈显著正相关,对个体生物量的贡献率为:茎>叶>根>花。多年生和1~2年生物种的个体生物量以及各构件生物量均无显著差异,但1~2年生物种的茎和地上生物量对个体生物量的贡献率显著高于多年生物种,而多年生物种的地下生物量对个体生物量的贡献率显著高于1~2年生物种,不同构件对生物量贡献率的差异有利于不同生活型植物的种群扩散和繁衍。

科尔沁沙地70种植物繁殖体形状比较研究

研究了科尔沁沙地70种植物的繁殖体(31种为种子,39种为果实)形状。用繁殖体三维(长、宽、高)的方差衡量繁殖体形状。方差越小,繁殖体越接近圆球形;方差越大,繁殖体越细长或扁平。研究结果表明,1)所量测的70种植物的繁殖体(种子或果实)形状差异很大,最小的方差不足0.03,最大的超过0.18。2)大部分一年生杂草的种子繁殖体近似于圆球形。3)黄蒿、马齿苋、碱地肤、狼尾花、灰绿藜、刺沙蓬、菟丝子、大籽蒿、狗尾草的繁殖体比较接近圆球形(方差小于0.09),它们可能具有持久种子库。4)萝摩科植物萝摩、杠柳、细叶白前繁殖体具绢毛;菊科植物女菀、飞廉、黄金菊、山莴苣、苣荬菜和夹竹桃科植物罗布麻有冠毛;石竹科植物石竹和鸢尾科植物野鸢尾有翅;香蒲科植物小香蒲有宿存花柱;可能这些植物都可被风传播。糙隐子草、披碱草、水稗草、牛鞭草、冠芒草具芒,它们可能具有固结自身的作用;苍耳、雾冰藜、鹤虱带钩或刺,易于被动物传播。5)草甸植物野豌豆、海滨天冬、小黄花菜作为传播体的种子较圆;草甸植物女菀、山莴苣、黄金菊、披碱草、野古草、牛鞭草、狼尾草作为传播体的果实扁平或细长;流沙上的先锋植物或沙生系列演替前期植物沙蓬、刺沙篷、乌丹蒿、差巴嘎蒿、狗尾草、雾冰藜、东北木蓼、山竹子等的繁殖体多数偏离圆