辽河三角洲植被结构、功能及其驱动机制

辽河三角洲优越的植被生态系统维系着多种生态功能，使该地区成为全国著名的商品粮基地、造纸原料基地和旅游基地。但是，气候变化和人为干扰使得辽河三角洲的植被结构发生了显著变化，影响到植被功能的发挥。 为了应对气候变化和人为干扰对辽河三角洲植被造成的不利影响，本论文围绕植被结构和生产功能，从空间和时间方面，重点阐述了辽河三角洲植被的结构及其驱动机制；辽河三角洲植被生产功能及其驱动机制。 采用的研究方法包括遥感解译、样带调查和全面调查。通过遥感解译方法获取各植被类型的面积、分布及其变化信息，以研究植被的空间分布格局及其变化。通过样带调查方法，获取植被类型、土壤和水文等信息，并结合规范对应分析和偏相关分析等，研究植被空间分布格局的驱动机制。通过全面调查方法，获取植被净第一性生产力、粮食产量、土壤和水文等信息，并结合地理信息系统(GIS)的插值分析和相关分析等，研究植被生产功能的空间分布格局及其驱动机制。主要结论如下： 1. 植被组成和空间格局：辽河三角洲植被主要由自然湿地植被、人工湿地植被、自然旱地植被、人工旱地植被四大植被类型组成。其中，面积最大的3种植被是玉米、水稻和芦苇。四大植被类型以双台子河口为中心，基本上呈现半环状分布格局。 2. 植被空间格局变化：1988～2006年辽河三角洲植被空间格局发生了显著变化，主要植被类型分布趋于集中，形成了一些较大的斑块，而不是离散和破碎。从面积上看，水稻是面积增加最多的植被类型；玉米是面积减少最多的植被类型。从变化速率看，水稻、玉米和芦苇的变化幅度都较大，分别为33.2%、-16.1%和-23.2% 。 3. 植被空间格局形成机制：辽河三角洲植被分布格局不是由气候因子决定的，而是由土壤因子决定。土壤可溶性盐是决定植被分布格局最重要的环境因子，其次是土壤含水量。 4. 植被生产功能：辽河三角洲植被具有极高的生产力。其中，玉米、水稻和芦苇3种主要植被的地上净第一性生产力分别为30,485、18,248和17,440 kg/(ha•a)。玉米和水稻单位面积粮食产量也非常高，分别为14,813和10,365 kg/(ha•a)。 5. 植被生产功能年际变化：辽河三角洲植被生产力存在明显的年际波动。1992～2005 年间玉米和水稻粮食产量呈现显著的年际波动；1949～1990 年间芦苇产量不仅存在较明显的年际波动，而且呈现非常显著的增加趋势。 6. 植被生产功能年际变化的驱动机制：气候因子是玉米和水稻粮食产量年际变化的主要驱动因子，气候因子对玉米和水稻粮食产量的影响远远大于人为因子（农业人口、施肥量、灌溉面积）的影响。气候因子和人为因子对芦苇产量年际变化的影响都非常显著。在气候因子中，年日照数是驱动玉米产量年际波动的主导气候因子；年降水量是驱动水稻产量年际波动的主导气候因子；年蒸发量是驱动芦苇产量年际波动的主导气候因子。 7. 植被生产功能空间格局：植被地上净第一性生产力存在显著的空间差异，表现为一种环形空间分布格局，三角洲中部较低，四周地区较高。这种空间分布格局表明，在辽河三角洲，植被地上净第一性生产力最高的不是湿地植被，而是周围旱地植被。 8. 植被生产功能空间格局的形成机制：土壤含水量和海拔是驱动辽河三角洲植被生产力空间格局的主要因子；土壤盐度、土壤pH和土壤容重对植被生产力的空间格局影响不大。土壤营养元素(氮、磷、钾) 对植被生产力的空间格局几乎没有影响。

On the selective action of the cod end meshes of a shrimp trawl

Selectivity studies using cod end and cover to determine the optimum cod end mesh size for commercial size groups of shrimps was carried out at Cochin during 1963-64 fishing season. The normality of the result was checked by trouser cod end method. Although the present investigation was mainly aimed to find out suitable cod end mesh size for commercial varieties of shrimps, five commonly occurring species of fishes were also taken. The 50% escape level, co-efficient of selectivity and selection factor for all the species were worked out. From the findings, the authors stress the necessity of increasing the cod end mesh size from the present condition (25.4 to 31.70 mm) to 41.65 mm fabricated mesh size to avoid depletion of the natural population.

Engineering design and mechatronics: The schemebuilder project

The paper describes the development of a software design aid for use at the conceptual stage of engineering design. It is intended for use in the design of mechatronic products but has wider potential uses. Early approaches were based on function structures and tables of options and the system that evolved allows the assembly of schemes linked by matching their input and output ports. A database of components is provided which can be accessed via different indexes and the designer can easily create and compare alternative schemes at the concept stage. A bond graph approach is used to define the interconnections between components. This allows correct port matching but also provides for future development such as constraint propagation through the design and links to simulation tools. © 1993 Springer-Verlag New York Inc.

A new, fast response CO2 sensor

The inability of emissions reduction methods to meet upcoming legislation without an unacceptable increase in vehicle cost is a major problem of automobile manufacturer. This work aims to develop a cost-effective reduction of automobile emissions. A prototype CO2 sensor with 5 msec response time was built and bench tested, then used on an engine. The sensor design was based on standard emissions measurement technology using non-dispersive IR absorption. An improved sensor has now been completed with significant improvements in terms of signal to noise ratio and long-term stability. The improved sensor will be used to measure CO2 concentrations on three different engines. The results will then be used to validate engine and catalyst models and to propose control strategies aimed at reducing overall emissions. A brief description of the sensor itself was presented. Original is an abstract.

Conserved chromosome segments in Hylobates hoolock revealed by human and H-leucogenys paint probes

A complete comparative chromosome map of the white-browed gibbon (Hylobates hoolock, 2n = 38), white-cheeked gibbon (Hylobates leucogenys, 2n = 52), and human has been established by hybridising H. leucogenys chromosome-specific paints and human 24-colour paints onto H. hoolock metaphase chromosomes. In the 18 H. hoolock autosomes, we identified 62 conserved segments that showed DNA homology to regions of the 25 H. leucogenys autosomes, Numerous interchromosomal rearrangements differentiate the karyotypes of H. leucogenys and H. hoolock. Only H. hoolock chromosome 10 showed homology to one entire autosome of H. leucogenys. The hybridisation of human 24-colour paints not only confirmed most of the chromosome correspondences between human and H. hoolock established previously but also helped to correct five erroneous assignments and revealed three new segments. Our results demonstrate that the karyotypes of the extant gibbons have arisen mainly through extensive translocation events and that the karyotype of H. hoolock more closely resembles the ancestral karyotype of Hylobates, rather than the karyotype of H. leucogenys. Copyright (C) 2001 S. Karger AG, Basel.

Construction of a BAC library for Chinese amphioxus Branchiostoma belcheri and identification of clones containing Amphi-pax genes

Amphioxus is a crucial organism for the study of vertebrate evolution. Although a genomic BAC library of Branchiostoma floridae has been constructed, we report here another BAC library construction of its distant relative species Branchiostoma belcheri. The amphioxus BAC library established in present study consists of 45,312 clones arrayed in one hundred and eighteen 384-well plates. The average insert fragment size was 120 kb estimated by Pulsed Field Gel Electrophoresis (PFGE) analysis of 318 randomly selected clones. The representation of the library is about 12 equivalent to the genome, allowing a 99.9995% probability of recovering any specific sequence of interest. We further screened the library with 4 single copied Amphi-Pax genes and identified total of 26 positive clones with average of 6.5 clones for each gene. The result indicates this library is well suited for many applications and should also serve as a useful complemental resource for the scientific community.

无指盘臭蛙皮肤活性肽及其基因和在制药中的应用

本发明涉及一种无指盘臭蛙皮肤活性肽及及其基因和在制药中的应用，属于生物医学领域。无指盘臭蛙皮肤活性肽是无指盘臭蛙皮肤活性肽基因编码的一种单链多肽，分子量3015.63道尔顿，等电点10.3，多肽全序列一级结构为： Ala Thr Ala Leu Gly Leu Ser Ser Arg Gly Leu Leu Pro Ile Gly Phe Met Phe Lys Asp Thr Ile Arg Cys Arg Lys Tyr(ATALGLSSRGLLPIGFMFKDTIRCRKY)。编码无指盘臭蛙皮肤活性肽的基因由312个核苷酸组成，其中编码成熟无指盘臭蛙皮肤活性肽为第141-222位核苷酸。人工合成的无指盘臭蛙皮肤活性肽具有很强的抑制细菌和真菌生长的作用，可以作为制备病原微生物感染疾病的治疗药物被应用。无指盘臭蛙皮肤活性肽具有结构简单、人工合成方便、抗菌谱系广、抗菌活性强的特点。

无指盘臭蛙臭蛙肽及其基因和在制药中的应用

本发明涉及一种无指盘臭蛙臭蛙肽及其基因和在制药中的应用，属于生物医学领域。无指盘臭蛙臭蛙肽是无指盘臭蛙臭蛙肽基因编码的一种单链多肽，分子量1814.11道尔顿，等电点8.08，多肽全序列一级结构为： Gly Cys Ser Arg Trp Ile Ile Gly Ile His Gly Gln Ile Cys Arg Asp。(GCSRWIIGIHGQICRD)。编码无指盘臭蛙臭蛙肽的基因由312个核苷酸组成，其中编码成熟无指盘臭蛙臭蛙肽为第141-189位核苷酸。人工合成的无指盘臭蛙臭蛙肽具有很强的抑制细菌和真菌生长的作用，可以作为制备病原微生物感染疾病的治疗药物被应用。本发明的无指盘臭蛙臭蛙肽具有结构简单、人工合成方便、抗菌谱系广、抗菌活性强的特点。

乳腺增生病p53基因第7外显子突变检测

目的探讨p53基固在乳腺癌发生早期的作用及早期诊断乳晾瘟的分子病理指标。方法用PCR—sso 法检测36例乳腺单纯性增生、31例不典型增生、14例原位癌和16例程润癌中p53基因第7外显子突变，井用叭A 直接测序技术确定突变的碱基及其所在的密码子。结果乳腺单纯性增生、不典型增生、原位癌、浸润癌中|】53基 因第7外显于的突变率分别为0％、6 5％(2／31)、21 4％(3／14)、18．8％(3／16)。8例突变中，3例发生于251密码 子，4例发生手248密码子，I例发生于236密码子。表现为碱基替换(5例)、缺失(2例)、插入(J例)共二种突变方 式。并在I例原位瘟中首次发现了251密码子的同义突变(ATC斗ATr，异亮氨酸一异亮氮酸)。结论乳腺癌不典 型增生中存在053基因第7外显子突变，该突变可能在乳腺不典型增生发展到乳腺癌的过程中起霞要作用，可作为 早期诊断乳腺癌的辅助指标。

双峰驼线粒体DNA地高辛标记探针的制备及其应用

利用地高辛标记技术，对从双峰驼肝脏和肾脏提纯的线粒体ＤＮＡ进行了标记，制成探针，并用它检测了包含于白细胞总ＤＮＡ中的微量线粒体ＤＮＡ。结果表明这一技术完全可以成功地用于微量线粒体ＤＮＡＲＦＬＰ的分析。