知母染色体核型的研究     

李林初  徐炳声 《中国科学院研究生院学报》1983,21(4):445-448

  A karyotypical analysis of Anemarrhena asphodeloides Bung. of the monotypic genus Anemarrhena Bung. (Liliaceae) was carried out for the first time. The number of chromo- somes in root-tip cell of the species was found to be 22, agreeing with that reported by Sato[12], although inconsistent in some other respects, such as position of  centromeres, length of chromosomes, and nucleoli, etc. (Table 1 ). According to the terminology defined by Levan et al.［8］, the karyotype formula is therefore 2n=22=2sm (SAT)+2sm+18m. Photomicrographs of the chromosome complements and idiogram of the karyotype are given   Fig. 1 and 2).       The karyotype of Anemarrhena asphodeloides shows explicitly to be asymmetrical, with three pairs of long chromosomes and eight pairs of short chromosomes. This specialized feature, when considered together with the rare occurrence of the basic chromosome number of 11 of the genus within the Tribe Asphodeleae of Liliaceae (see Table 1), suggests that the genus Anemarrhena is probably a rather specialized one, which has scarcely any intimate relationship with the other genera of the above tribe. The fact that this specialized karyotype is associated with certain trends of morphological specialization, such as flowers possessing three stamens only, gives support to the above suggestion. But, it is impossible to draw a more precise conclusion without a more thorough and comprehensive investigation of the species in question.  相似文献   

舟山群岛植物区系地理的数值研究     

郝思军  徐炳声  缪柏茂 《中国科学院研究生院学报》1989,27(6):405-420

本文根据对舟山群岛种子植物348个种(及种以下分类单位)在18个地理单位的分布状况进行 计算机聚类分析和主成分分析(PCA)，表明了该群岛与我国大陆的浙江和江苏植物区系有着密切的亲 缘关系和相似性；与日本和我国台湾植物区系的联系则不如一般所认为的那样接近，当然，仍有不少十 分有意义的连锁植物存在于三者之间。     舟山群岛在植物区系区划上应为中亚热带北部亚地带，区系特点之一是岛屿植物较发达，而山地森 林区系则与我国南方植物区系相接近。  相似文献   

AS/RS based yard and yard planning     

Ya-hong Hu  Zheng-dong Zhu  Wen-jing Hsu 《浙江大学学报(A卷英文版)》2008,9(8):1083-1089

In this paper, we apply the split-platform automated storage/retrieval systems （SP-AS/RSs） （Hu et al., 2005） to store containers in the yard to improve the yard performance and to increase the utilization of the yard space. The layout of an SP-AS/RS based yard is described in detail. To achieve an efficient operation, we present a novel yard space allocation policy called the ＇second-carrier-based allocation policy＇, which can help to alleviate the out-of-sequence problem of containers and the congestion of vehicles at the AS/RS racks. Different allocation policies are compared by an integrated container terminal simulation system. The simulation results show that the second-carrier-based policy is very efficient and has the potential to offer high terminal performance.  相似文献   

A simple and inexpensive enteric-coated capsule for delivery of acid-labile macromolecules to the small intestine     

Darren S. Miller  Anne Michelle Parsons  John Bresland  Paul Herde  Duc Minh Pham  Angel Tan  Hung-yao Hsu  Clive A. Prestidge  Tim Kuchel  Rezaul Begg  Syed Mahfuzul Aziz  Ross N. Butler 《Journal of Zhejiang University. Science. B》2015,16(7):586-592

Understanding the ecology of the gastrointestinal tract and the impact of the contents on the host mucosa is emerging as an important area for defining both wellness and susceptibility to disease. Targeted delivery of drugs to treat specific small intestinal disorders such as small bowel bacterial overgrowth and targeting molecules to interrogate or to deliver vaccines to the remote regions of the small intestine has proven difficult. There is an unmet need for methodologies to release probes/drugs to remote regions of the gastrointestinal tract in furthering our understanding of gut health and pathogenesis. In order to address this concern, we need to know how the regional delivery of a surrogate labeled test compound is handled and in turn, if delivered locally as a liquid or powder, the dynamics of its subsequent handling and metabolism. In the studies we report on in this paper, we chose ¹³C sodium acetate (¹³C-acetate), which is a stable isotope probe that once absorbed in the small intestine can be readily measured non-invasively by collection and analysis of ¹³CO₂ in the breath. This would provide information of gastric emptying rates and an indication of the site of release and absorptive capacity. In a series of in vitro and in vivo pig experiments, we assessed the enteric-protective properties of a commercially available polymer EUDRAGIT®L100-55 on gelatin capsules and also on DRcaps®. Test results demonstrated that DRcaps®coated with EUDRAGIT®L100-55 possessed enhanced enteric-protective properties, particularly in vivo. These studies add to the body of knowledge regarding gastric emptying in pigs and also begin the process of gathering specifications for the design of a simple and cost-effective enteric-coated capsule for delivery of acid-labile macromolecules to the small intestine.  相似文献   

四川白珠树属二新种     

徐廷志 《中国科学院研究生院学报》1992,30(2):175-178

Gaultheria lasiocarpa T. Z. Hsu and G. miyienensis T. Z. Hsu (Ericaceae) are des-cribed as new from Sichuan Province, China.  相似文献   

吉祥草染色体核型的研究     

徐炳声  李林初 《中国科学院研究生院学报》1984,22(2):128-130

Karyotype analysis for the species Reineckia carnea (Andr.) Kunth of the mo- notypic genus Reineckia Kunth is given for the first time. The number of chromosomes in root-tip cell was found to be 38, which is in accord with those reported by most of the pre- vious authors[5,7,8,9,11,12,]. The somatic complement shows a slight variation in size, i.e., the 2, 3, 5, 6, 7th pairs of the chromosomes have submedian constrictions, while the other pairs have median centromeres. The karyotype is therefore a rather symmetrical one, and accor- ding to the chromosomal terminology defined by Levan et al[4], the karyotype formula of the species is 2n=38=28 m+10 sm. In spite of the presence of two nucleoli in the te- lophase as observed by the authors and Noguchi[8] as well, the two corresponding Sat-chro- mosomes have not been found.  Photomicrograph of the chromosome complement and idiog- ram are given in Fig. 1 and 2 respectively.  相似文献   

Entrepreneurs from technology-based universities: Evidence from MIT     

David H. Hsu  Edward B. Roberts 《Research Policy》2007,36(5):768-788

This paper analyzes major patterns and trends in entrepreneurship among technology-based university alumni since the 1930s by asking two related research questions: (1) Who enters entrepreneurship, and has this changed over time? (2) How does the rate of entrepreneurship vary with changes in the entrepreneurial business environment? We describe findings based on data from two linked datasets joining Massachusetts Institute of Technology (MIT) alumni and founder information. New company formation rates by MIT alumni have grown dramatically over seven decades, and the median age of first time entrepreneurs has gradually declined from about age 40 (1950s) to about age 30 (1990s). Women alumnae lag their male counterparts in the rate at which they become entrepreneurs, and alumni who are not U.S. citizens enter entrepreneurship at different (usually higher) rates relative to their American classmates. New venture foundings over time are correlated with measures of the changing external entrepreneurial and business environment, suggesting that future research in this domain may wish to more carefully examine such factors.  相似文献   

中国荚蒾属分布式样的数值分析     

徐炳声  缪柏茂 《中国科学院研究生院学报》1988,26(5):329-342

    本文用数值分类的关联分析方法对国产荚蒾属 Viburnum  所有72种的分布式样进行     了研究，旨在为中国植物区系分区的工作提供若干依据。中国荚蒾属的遗传变异中心是在中     南部而不在南部或西南部的事实强烈地暗示这是一个亚热带性质的属。  四川西南部是西部     特有成分最密集的地区。尽管横断山脉地区地形复杂，但那里只有几种荚蒾属植物。台湾的     种主要是亚热带性质的，而且大多数与大陆的种相同。这些种的分布式样展示我国台湾在区     系地理上与我国大陆或甚至日本有着比马来西亚地区更密切的亲缘关系。  本文总的结论大     体上与吴征镒教授关于中国种子植物区系的分区相符，但在某些次要方面有所不同。作者还    讨论了种的分布式样与自然地理、气候和植被的联系。  相似文献   

胡枝子种内地形梯度变异的分析     

徐炳声  李学禹  顾德兴 《中国科学院研究生院学报》1983,21(3):306-318

 Owing to the diagnostic characters used for distinguishing Lespedeza bicolor Turcz. from its allies L. formosa (Vogel) Koehne and L. elliptica Benth. ex Maxim. etc. beiny totally quantitative, and the great variability found in themselver as well, the group is therefore regarded as a taxonomically perplexing one. Therefore  quantitative measurements of the diagnostic characters, namely, the lengths of flowers (including standards and keels) and calyces (including calyx teeth and tubes) upon the total 307 herbarium sheets collected from 22 provinces and autonomous regions were made, and the data obtained were treated statistically (Table 1) and compared using methods of scatter diagram (Fig. 1--5),polygraph (Fig. 6) and topoclinal variation  (Fig. 7--10) in order to bring to light the differentiation pattern of these characters correlated to geographical distribution.      The diagrams of topoclinal variation (Fig. 7--10) of single characters represented by the lengths of calyx-teeth and corolla, or the calyx-teeth/calyx-tube ratio, between which exists a strong positive correlation, show a tendency of increasing gradation from northeast towards south-west. But the different combinations of morphological characters as shown in the scatter diagrams and more particularly in the polygraphs, make it possible to divide the Lespedeza bicolor group into the following three geographical types: (1) Bicolor type, with the distributional area of four provinces and one autonomous region of north-eastern and northern China; having the shortest (shorter than the calyx-rube) calyx-teeth of the whole group; with the standards of 71% herbarium materials exceeding the keels;  the  corolla length/calyx length ratio being 2.24; (2) Formosa type, with the distributional area covering six provinces and one autonomous region of eastern, south-eastern and southern China; with calyx-teeth nearly as long as calyx-tuges; with the keels of 69% herbarium sheets exceeding the standards, including all from whole  Guangdong  (Kwantung)  and  Guangxi (Kwansi); the corolla length/calyx length ratio being 2.59, the largest among the group; (3) Elliptica type, with the largest distributional area occupying ten provinces of south western, central, northwestern and eastern China and with most complicated morphologi- cal variation; the range of calyx-teeth length being 1.23--5.53 mm; with the keels of 80% herbarium sheets exceeding the standards, including all from whole Hubei (Hupeh) and Sichuan ( Szechuan ).      Since the above geographical types are either transitional or overlapping, it is probably appropriate to regard them as different geographical subspecies of a single species Lespedeza bicolor Turcz. Taxonomic treatments are then made herewith. A comparison of the main diagnostic characters and distributional patterns of the three subspecies in question is given in Table 3.  相似文献   

石蒜属的核型研究   总被引：3，自引：0，他引：3  

刘琰  徐炳声 《中国科学院研究生院学报》1989,27(4):257-264

本文对石蒜属Lycoris的12个种(包括亚种)和2个人工杂种进行了核型分析。 结果表明，石蒜属植物在染色体数目和核型上存在着较大的变异，而罗伯逊变化、杂交与多倍化是引起染色体变异的主要原因。  相似文献