Variational Approach to the Thomas-Fermi Equation

By the semi-inverse method, a variational principle is obtained for the Thomas-Fermi equation, then the Ritz method is applied to solve an analytical solution, which is a much simpler and more efficient method.

Mitochondrial cytochrome b gene sequence diversity in the Korean hare, Lepus coreanus Thomas (Mammalia, Lagomorpha)

Partial sequences of the mitochondrial cytochrome b gene of the Korean hare (Lepus coreanus) were analyzed to determine the degree of genetic diversity. Nine haPlotyes were observed, and the maximum Tamura-Nei nucleotide distance among them was 2.8%, indicating that genetic diversity of L. coreanus is moderate. In order to clarify the Korean hare's taxonomic status and relationship with the Manchurian hare (L. mandshuricus) and the Chinese hare (L. sinensis), these nine haplotypes of the Korean hare were compared with 13 haplotypes from five other species of eastern Asian Lepus including L. mandshwicus and L. sinensis. The Korean hare was distinct in its cytochrome b gene, and it is confirmed that L. coreanus is a valid species, as noted by Jones and Johnson (1965, Univ. Kansas Publ. (Mus. Nat. Hist.) 16:357). Further analyses of mtDNA cytochrome b gene with additional specimens of L. coreanus from North Korea and other species of Lepus from eastern Asia are needed to clarify the taxonomic status of the divergent mtDNA clades of L. mandshuricus and L. sinensis.

亚洲南部球果蝠Sphaerias blanfordi(Thomas,1891)的亚种分化

球果蝠Sphaerias blanfordi(Thomas,1891)是亚洲南部喜马拉雅-印度支那地区的特有种,甚为罕见而少有报道.曾被认为是单型种,几乎无雄性特征的描述.蔡桂全和张遁治(1980)根据采自西藏东南部墨脱的2只雄性标本订了一亚种一墨脱亚种Sphaerias blanfordi motuoensis,其主要特征是颈下侧有一对灰黄色的圆形毛斑.中国科学院昆明动物研究所先后在云南西北部高黎贡山地区采获25号标本(9♂♂,16♀♀),发现球果蝠两性在外形上有明显的性别差异,雄性的颈下侧有一对圆形、灰黄色的刷状毛斑,但雌性均无;对比墨脱标本,认为墨脱亚种的鉴别特征不可靠,亚种不能成立.Lunde(2003)曾报道采自越南北部Mt.Tay Con Linh Ⅱ地区的43号标本,其前臂长和上犬齿外宽明显与印度、缅甸和云南西北部高黎贡山地区的标本不同,可能是真正的地理亚种.

Geographic variation of the Anderson's Niviventer (Niviventer andersoni) (Thomas, 1911) (Rodentia: Muridae) of two new subspecies in China verified with cranial morphometric variables and pelage characteristics

A total of 66 specimens of Niviventer andersoni with intact skulls was investigated on pelage characteristics and cranial morphometric variables. The data were subjected to principal component analyses as well as to discriminant analyses, and measurement

Gynogenesis and sex determination in large-scale loach Paramisgurnus dabryanus (Sauvage)

Gynogenesis was induced using heterologous sperms in large-scale loach, Paramisgurnus dabryanus (Sauvage), in which a ZW/ZZ sex determination was previously proposed. Three microsatellite loci were used to monitor exclusive maternal inheritance of gynogenetic progenies. The results showed that high percentages of meiogynogens were produced at 4 min post-fertilization and mitogynogens were produced at 18 min post-fertilization by heat shocks, while meiotic gynogenesis was induced by cold shocks within a wide period and high heterozygosity was even observed in gynogens produced at 24 min post-fertilization. The sex ratios of the F, progenies in three gynogenetic families were significantly deviated from 1: 1 expectation with a female bias in two families and a male bias in one family (P < 0.05), and the other four gynogenetic families showed approximate 1:1 sex ratios. Moreover, the self-mating between gynogenetic F, progenies and mating between gynogenetic F, progenies and normal individuals produced all-female progenies or identical proportions of females and males. The data of sex ratios generally confirmed that the sex determination in large-scale loach was determined by the putative ZW/ZZ system, and the possible reasons causing the biased sex ratios are discussed.

Nuclear transfer in leach (Paramisgurnus dabryanus Sauvage) by cell-to-cell electrofusion

To study nuclear transfer in the leach (Paramisgurnus dabryanus Sauvage), blastula and gastrula cells were fused with UV-inactivated oocytes by cell-to-cell electrofusion. To facilitate nuclear transfer, blastula and gastrula cells were cultured or incubated at 4 degreesC in different solutions. TC-199 medium supplemented with 20% calf serum was the best culture solution, and effectively retained the totipotence of blastula or gastrula cells for up to 10 days, It was found that gastrula cells incubated at 4 degreesC had the same totipotence as blastula cells, The optimal UV dosage for inactivation of the oocyte chromatin was 180-240 mJ cm(-2). Electrofusion was carried out in a cone-shaped fusion chamber, which permitted the recipient oocyte and the donor blastula cell to contact one another. The electrofusion procedure resulted in a 10% success rate of normal-appearing fish. Genetic analysis indicated that the nuclear material originated from the donor cell (blastomere) and the oocyte pronucleus did not take part in development.