Chromosomal mapping of the major ribosomal RNA genes in the dwarf surfclam (Mulinia lateralis Say)

Chromosomal location of the major ribosomal RNA genes (rRNA) were studied in the dwarf surfclam (Mulinia lateralis, Say) using fluorescence in situ hybridization (FISH). FISH probes for the rRNA genes were made by polymerase chain reaction (PCR), labeled with digoxigenin-11-dUTP and detected with fluorescein-labeled antidigoxigenin antibodies. Mulinia lateralis had a diploid number of 38 chromosomes and all chromosomes were telocentric. FISH with the rRNA probe produced positive and consistent signals on two pairs of chromosomes: Chromosome 15 with a relative length of 4.6% and Chromosome 19, the shortest chromosome. Both loci were telomeric. The rRNA location provides the first physical landmark of the M. lateralis genome.

Study on corrosion simulation device for marine structural steel

A corrosion simulation device was studied using offshore long scale hanging specimens. An Ni-Cu-P steel specimen was studied by analysing its corrosion products and corrosion types. The appearance of the samples and the surface of the metallic substrate after the removal of the rust layer produced by these two methods were observed and compared after 470 days of exposure. The phase structure of the corrosion products under different marine environments were analysed and compared. It further indicated good correlation between the electrically connected hanging specimen method and the long scale hanging specimen method.

青海群加地区种植大黄根茎组织结构中微量元素特征

微量元素对于种植青海大黄的生长发育有着重要作用.采集青海群加地区种植大黄根茎,分为皮层、韧皮部、木质部和髓部等四部分,采用原子吸收光谱法分别测试了其不同组织中铜、锌、铁、锰、钴、镍等元素含量.结果表明,种植大黄根茎中铜、锌、铁、锰等元素主要分布在皮层,其次是木质部或髓部,元素含量较低的是韧皮部.随着生长年龄增加种植大黄对铁、锰、钴元素营养需求量有所增加,对锌、铜、镍元素营养的需求量略减.

环境因子对暗沃寒冻雏形土土壤CO_2释放速率的影响

暗沃寒冻雏形土土壤CO2 释放的日变化与气温及地表温度的日变化过程同步, 只是气温日变化峰值推迟了2 h。地表温度与土壤CO2 释放速率呈极显著正相关。暗沃寒冻雏形土土壤CO2 释入的季节动态受土壤温度(0～ 30cm , 特别是10 cm )、真菌菌丝生物量(0～ 20 cm )、土壤有机碳现存量(0～ 20 cm ) 和生物量的影响。它们均与土壤CO2 的释放速率呈显著或极显著的正相关关系。过度放牧使土壤容重增大, 孔隙度和土壤有机碳贮量减小, 从而降低土壤CO2 释放速率, 方差分析结果表明, 差异显著。而土壤湿度及降雨对土壤CO2 释放速率影响较小。

Molecular phylogeny and biogeography of the Qinghai-Tibet Plateau endemic Nannoglottis (Asteraceae)

All taxa endemic to the Qinghai-Tibet Plateau are hypothesized to have originated in situ or from immediately adjacent areas because of the relatively recent formation of the plateau since the Pliocene, followed by the large-scaled biota extinction and recession caused by the Quaternary ice sheet. However, identification of specific progenitors remains difficult for some endemics, especially some endemic genera. Nannoglottis, with about eight species endemic to this region, is one such genus. Past taxonomic treatments have suggested its relationships with four different tribes of Asteraceae. We intend to identify the closest relatives of Nannoglottis by evaluating the level of monophyly, tribal delimitation, and systematic position of the genus by using molecular data from ndhF gene, trnL-F, and ITS region sequences. We find that all sampled species of Nannoglottis are a well-defined monophyly. This supports all recent taxonomic treatments of Nannoglottis, in which all sampled species were placed in one broadly re-circumscribed genus. Nannoglottis is most closely related to the Astereae, but stands as an isolated genus as the first diverging lineage of the tribe, without close relatives. A tentative relationship was suggested for Nannoglottis and the next lineage of the tribe was based on the ITS topology, the "basal group," which consists of seven genera from the Southern Hemisphere. Such a relationship is supported by some commonly shared plesiomorphic morphological characters. Despite the very early divergence of Nannoglottis in the Astereae, the tribe must be regarded to have its origin in Southern Hemisphere rather than in Asia, because based on all morphological, molecular, biogeographical, and fossil data, the Asteraceae and its major lineages (tribes) are supposed to have originated in the former area. Long-distance dispersal using Southeast Asia as a steppingstone from Southern Hemisphere to the Qinghai-Tibet Plateau is the most likely explanation for this unusual biogeographic link of Nannoglottis. The 23-32-million-year divergence time between Nannoglottis and the other Astereae estimated by DNA sequences predated the formation of the plateau. This estimation is further favored by the fossil record of the Asteraceae and the possible time of origin of the Astereae. Nannoglottis seems to have reached the Qinghai-Tibet area in the Oligocene-Eocene and then re-diversified with the uplift of the plateau. The molecular infragenetic phylogeny of the genus identifies two distinct clades, which reject the earlier infrageneric classification based on the arrangement of the involucral bracts and the length of the ligules, but agree well with the habits and ecological preferences of its current species. The "alpine shrub" vs. "coniferous forest" divergence within Nannoglottis was estimated at about 3.4 million years ago when the plateau began its first large-scale uplifting and the coniferous vegetation began to appear. Most of the current species at the "coniferous forest" clade of the genus are estimated to have originated from 1.02 to 1.94 million years ago, when the second and third uprisings of the plateau occurred, the climate oscillated and the habitats were strongly changed. The assumed evolution, speciation diversity, and radiation of Nannoglottis based on molecular phylogeny and divergence times agree well with the known geological and paleobotanical histories of the Qinghai-Tibet Plateau. (C) 2002 Elsevier Science (USA). All rights reserved.

旋翼飞行机器人飞行控制系统设计

本文以小型模型直升机为研究对象，详细描述了旋翼飞行机器人自主飞行控制系统的软硬件以及控制器设计.此飞行机器人模型可作为先进控制方法验证的优秀平台，并以此提高其可靠性、可操作性以及自主行为能力.此安装有控制器及传感器组的旋翼飞行机器人已经在地面飞行控制站的遥控指令下成功进行了飞行实验，采集了相关的位置、姿态等数据，并给出了一种用于自主飞行的控制策略。

岩溶生态系统脆弱性剖析

生态系统的脆弱性评价对于生态系统管理具有重要作用。在分析岩溶生态系统脆弱性特征和影响因素的基础上,构建了针对岩溶自然系统的脆弱性评价指标体系,涵盖了岩溶生态系统的结构脆弱性、生态过程脆弱性、生态功能脆弱性和人为胁迫脆弱性4个方面,评价指标分别是结构稳定性、多样性生境、能量利用和积累、直接使用价值、石漠化程度和速率等。以不同类型的原生岩溶生态系统的生态基准值作为比较基础,评价系统将现有的退化岩溶生态系统的脆弱性划分为轻微脆弱、中度脆弱、重度脆弱以及系统崩溃4级

浅论扬子西南缘卡林型金矿成矿物质来源及有机质在成矿过程中的作用

在前人研究的基础上，对扬子西缘卡林型金矿采用稳定同位素和生物化学试验方法，分析赋金地层中有机质的种类、性质和有机质与金矿的关系，讨论有机质在金元素富集、迁移、成矿过程中的作用。认为赋金地层与后期岩浆热液发生广泛的交换作用，萃取出成矿物质形成成矿流体，这种富含成矿物质的热液流体在一定的条件下富集成矿。

河南小秦岭大湖金－钼矿床地球化学及其矿床成因

秦岭造山带是华北与扬子两大古板块的接合带，在空间上，自北而南，秦岭造山带可分为华北板块南缘（华熊地块）、北秦岭造山带、南秦岭造山带和扬子板块北缘等4个构造单元。小秦岭金矿田位于华熊地块北缘，是国内外学者共识的造山型金矿田，河南灵宝大湖金－钼矿床位于小秦岭金矿田，属断控脉状矿床。大湖金－钼矿床最先正是以金矿床进行勘查的，其黄金储量28t，平均品位8.7g/t。随着开采深度的加大，部分含金石英脉向深部转变为辉钼矿－石英脉，目前探明钼资源量已达中型规模。 本论文主要从区域地质背景、矿床地质特征、元素地球化学、同位素地球化学、流体包裹体地球化学、矿床年代学及成矿机理等角度对大湖金－钼矿床进行了较为系统的研究，主要获得如下认识： 成矿过程经历3个阶段：早阶段为黄铁矿-石英脉，遭受变形、破碎，应形成于挤压或压剪过程；中阶段为细粒的辉钼矿-黄铁矿-石英网脉，贯入到早阶段黄铁矿或石英矿物的裂隙（可呈共轭状），应形成于剪切环境；晚阶段石英-碳酸盐细脉具梳状构造，充填于张性或张扭性裂隙。 大湖金-钼矿床的金属硫化物ISr=0.70470-0.71312，平均0.70854；(143Nd/144Nd)i=0.51143-0.51215，平均0.51162；(206Pb/204Pb)i=17.033-17.285，(207Pb/204Pb)i=15.358-15.438，(208Pb/204Pb)i = 37.307-37.582。其围岩太华群样品平均值ISr＝0.72294，(143Nd/144Nd)i=0.51107，(206Pb/204Pb)i=17.127-18.392，(207Pb/204Pb)i =15.416-15.604，(208Pb/204Pb)i=37.498-37.814，它们的平均值分别是17.547，15.470，37.616。通过金属硫化物及围岩太华群的对比，可以看出，成矿物质具有太华群和深部地幔混合的特征。 通过对不同阶段的含矿石英脉中的流体包裹体特征研究表明，早阶段只发育CO2-H2O型流体包裹体；中阶段流体包裹体类型复杂，有纯CO2型、CO2-H2O型、H2O-NaCl型和含子晶包裹体，指示流体沸腾作用强烈；而晚阶段只发育水溶液包裹体。早、中、晚3个阶段的流体包裹体均一温度分别集中在400-500℃、290-470℃、220-260℃；估计的早、中阶段流体的最低捕获压力分别为138-331MPa和78-237MPa，对应于成矿深度分别为13.8-11.0km和7.8-8.0km。早、中阶段的压力反应出静岩压力到静水压力的转变。成矿温度和压力明显高于浅部含金石英脉的成矿温度120-310℃，成矿压力100-150MPa。与野外观察到的“上金下钼”的空间关系一致。 大湖金－钼矿床辉钼矿－石英脉Re-Os同位素模式年龄较集中，介于215.4±5.4－255.6±9.6Ma，Re-0s等时线年龄为218±41Ma(MSWD=38，2σ误差)，表明大湖金－钼矿的辉矿化形成于印支期。 三叠纪末，随着古秦岭洋的逐渐封闭，处在弧后转换带的深部岩石在挤压作用下发生变质脱水而形成初始成矿流体，成矿流体沿断裂带（韧性剪切带）向上迁移而引起大湖钼矿床成矿系统的发育。随着区域构造环境由挤压转为伸展，区域的变质脱水更强，形成大量成矿流体，变质流体上侵为浅层流体循环提供了的热能，而浅层构造也因减压扩容而为流体循环提供了通道，这无疑有利于浅层流体循环和混入成矿系统。同时，增温和减压也有利于成矿流体发生沸腾。因此，充足的流体、热以及强烈的流体沸腾等，势必导致发生最为强烈的成矿物质快速沉淀作用。随着挤压作用的减弱，伸展作用的增强，区域热异常消失，地壳深部组分发生亏损，流体以浅源大气降水占主导，成矿作用迅速衰竭，形成石英-碳酸盐网脉，对成矿作用贡献减弱。总之，通过对大湖金钼矿床研究表明，大湖金钼矿床形成于由挤压转向伸展的构造背景，这与矿床地质的特征一致。

Characterization of polyethylene glycol-modified proteins by semi-aqueous capillary electrophoresis

A new program to characterize polyethylene glycol-modified (PEGylated) proteins is outlined using capillary zone electrophoresis (CZE). PEGylated ribonuclease A and lysozyme were selected as examples. Five separation procedures were compared to select out the mixed buffer of acetonitrile-water (1:1, v/v) at pH 2.5 as the best to characterize the PEGylated proteins without sample pretreatment. Polyethylene oxide (PEO) with a high molecular mass of 8X10(6) was applied to rinse the capillary to form a dynamic coating which would decrease the undesirable proteins adsorbed to the inner wall of the silica. The electroosmotic flow (EOF) mobility of the five procedures was determined, respectively. It is found that acetonitrile is mainly responsible for the good resolution of PEGylated proteins with the help of PEO coating in the semi-aqueous system. The low EOF mobility and current in the semi-aqueous system might also have some responsibility for the high resolution. The semi-aqueous procedure described in this paper also demonstrates higher resolution of natural proteins than aqueous ones. (C) 2001 Elsevier Science B.V. All rights reserved.

Reversed-phase high-performance liquid chromatographic investigation of urinary normal and modified nucleosides of cancer patients

Post-transcriptional modifications in RNA give rise to free modified ribonucleosides circulating in the blood stream and excreted in urine. Due to their abnormal levels in conjunction with several tumor diseases, they have been suggested as possible tumor markers. The developed RP-HPLC method has been applied to analyze the urinary nucleosides in 34 urinary samples from 15 kinds of cancer patients. The statistical analyses showed the urinary nucleoside excretion, especially modified nucleoside levels, in cancer patients were significantly higher than those in normal healthy volunteers. Factor analysis was used to classify the patients with cancer and normal healthy humans. It was found that using 15 urinary nucleoside levels or only five modified nucleoside levels as data vectors the factor analysis plot displayed two almost separate clusters representing each group. (C) 1999 Elsevier Science B.V. All rights reserved.

Estimativa da superfície específica de solos e do coeficiente de sorção de pesticidas.

São apresentados dois modelos de regressão linear múltipla. O primeiro foi obtido para estimar a superfície específica (SE) de solos brasileiros tendo como variáveis independentes os conteúdos volumétricos de argila, areia, silte e carbono orgânico. Tomou-se o cuidado para que o modelo proposto respeitasse restrições físicas de positividade dos valores da superfície específica, impondo-se restrições na determinação dos coeficientes dos atributos do modelo. Posteriormente, determinou-se uma relação linear múltipla para estimar o logaritmo decimal do coeficiente de sorção de pesticidas (LogKd) por meio da superfície específica do solo, do coeficiente de partição entre o octanol e a água, da solubilidade aquosa do pesticida e do pH do solo. Os modelos ajustados explicam 82% e 78% da variabilidade das variáveis dependentes SE e LogKd, respectivamente. Foram utilizados dados de 307 perfis de solos para a determinação da relação entre a superfície específica e os atributos do solo e 118 valores de coeficientes de sorção medidos experimentalmente para 20 pesticidas em 46 dados de solos representativos do ambiente agrícola brasileiro. Todos os dados deste estudo foram coletados em trabalhos científicos publicados. Os modelos apresentados podem facilitar o trabalho da previsão da superfície específica de solos (SE) e do coeficiente de sorção de pesticidas (Kd), contribuindo na estimativa da concentração ambiental de pesticidas por modelos matemáticos ou por índices que usem esses parâmetros em seus cálculos.

Generating Circuit Tests by Exploiting Designed Behavior

This thesis describes two programs for generating tests for digital circuits that exploit several kinds of expert knowledge not used by previous approaches. First, many test generation problems can be solved efficiently using operation relations, a novel representation of circuit behavior that connects internal component operations with directly executable circuit operations. Operation relations can be computed efficiently by searching traces of simulated circuit behavior. Second, experts write test programs rather than test vectors because programs are more readable and compact. Test programs can be constructed automatically by merging program fragments using expert-supplied goal-refinement rules and domain-independent planning techniques.