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1.
According to newly collected and well preserved specimens,herbaceous lycopsids Colpodexylon gracilentum Dou and Colpodexylon laminatum Dou from the late Middle Devonian of Xinjiang,NW China are reduced to C.gracilentum,for which a neotype is designated and emended diagnosis is given.Colpodexylon gracilentum has leaves with three nearly equal segmems,an elliptical sporangium adaxially attached by a pad on the isomorphic sporophyll.  相似文献   

2.
According to newly collected and well preserved specimens,herbaceous lycopsids Colpodexylon gracilentum Dou and Colpodexylon laminatum Dou from the late Middle Devonian of Xinjiang,NW China are reduced to C.gracilentum,for which a neotype is designated and emended diagnosis is given.Colpodexylon gracilentum has leaves with three nearly equal segments,an elliptical sporangium adaxially attached by a pad on the isomorphic sporophyll.  相似文献   

3.
A small dinoflagellate, ~13 μm in cell length, was isolated from Jinhae Bay, Korea. Light microscopy showed that it was similar to the kleptoplastidic dinoflagellate Gymnodinium gracilentum nom. inval. rDNA sequences were obtained and its anatomy and morphology described using light and scanning and transmission electron microscopy. Phylogenetic analyses indicated that it belonged to the family Kareniaceae. However, its large subunit (LSU) rDNA sequences were 5.2–9.5% different from those of the other five genera in the family, and its clade was clearly divergent from that of each genus. Its overall morphology was different from those of the other five genera in the family and from Gymnodinium. Unlike Gymnodinium, this dinoflagellate did not have a horseshoe‐shaped apical groove, nuclear envelope chambers, or a nuclear fibrous connective (NFC). It had an apical line of narrow amphiesmal vesicles and an elongated apical furrow crossing the apex. Cells were covered with polygonal amphiesmal vesicles arranged in 16 rows. Starved cells did not contain their own plastids, eyespots, pyrenoids, peridinin, or fucoxanthin. However, they could survive without added prey for approximately one month using chloroplasts from the cryptophyte prey Teleaulax amphioxeia, indicating kleptoplastidy. Because this taxon is genetically distinct at the generic rank from the other genera in Kareniaceae, it is placed in Shimiella gen. nov., and because G. gracilentum was invalid, the new bionomial S. gracilenta sp. nov. is proposed.  相似文献   

4.
News notes     

FERTILITY AND SURVIVAL, POPULATION PROBLEMS FROM MALTHUS TO MAO TSE‐TUNG: Alfred Sauvy. Translated by Christine Brooke‐Rose, Criterion Books Inc., New York, 1961, 232 pp. (simultaneously Chatto &; Windus Ltd., London).

l COLOMBO, BERNARDO, 1961. In: Rivista Internazionale di Science Sociali, 64: (5): pp. 505–12.

MIRAGE OF HEALTH: Rene Dubos. Dou‐bleday and Company, Inc. (Anchor Books), New York, 1961, 230 pp., $0.95.

POPULATION CONTROL, THE IMMINENT WORLD CRISIS: Melvin G. Shimm and Robinson O. Everett (Ed.). Oceana Publications, Inc., New York, 1961, pp. iv + 254, $6.00.  相似文献   

5.
Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) ovules were used to study male gamete formation, insemination of the egg, and free nuclear and cellular proembryo development. Two male nuclei form as the pollen tube either reaches the megaspore wall or as it enters the archegonial chamber. No cell wall separates them. They are contained within the body-cell cytoplasm. A narrow extension of the pollen tube separates the neck cells and penetrates the ventral canal cell. The pollen tube then releases its contents into the egg cytoplasm. The two male gametes and a cluster of paternal organelles (plastids and mitochondria) migrate within the remains of the body-cell cytoplasm toward the egg nucleus. Microtubules are associated with this complex. The leading male gamete fuses with the egg nucleus. The zygote nucleus undergoes free nuclear division, but the cluster of paternal organelles remains discrete. Free nuclei, paternal and maternal nucleoplasm, maternal perinuclear cytoplasm, and the cluster of paternal organelles migrate en masse to the chalazal end of the archegonium. There, paternal and maternal organelles intermingle to form the neocytoplasm, the nuclei divide, and a 12-cell proembryo is formed. The importance of male nuclei or cells, the perinuclear zone, and large inclusions in cytoplasmic inheritance are discussed in the Pinaceae and in other conifer families. This completes a two-part study to determine the fate of paternal and maternal plastids and mitochondria during gamete formation, fertilization, and proembryo development in Douglas fir.  相似文献   

6.
基于《国际植物命名法规(维也纳法规)》,文中简要讨论了志留纪晚Pridoli世拟莱尼蕨植物Junggaria (准噶尔蕨属)命名中存在的突出问题,指出过去使用的JunggariaDou,1983以及J·spinosa Dou,1983和J.sphaerica (Senkevitsch) Cai,1995均未合格发表。因...  相似文献   

7.
This paper describes a new plant—Stachyophyton yunnanense gen. et sp. nov., from Posongchong Formation (Siegenian) of the Lower Devonian in Wenshan district, Yunnan, China. This plant shows some similar organization in fertile region and sterile parts in comparison with other Devonian genera (Protolepidodendron, Colpodexylon, Leclercqia, Enigmophyton, Krithodeophyton). It may be that the plant represents an intermediate stage in evolution between Enigmophyton and Krithodeophyton, and shows perhaps a certain affinity to lycopods. According to the salient features of Stachyophyton, it can not be, at present, placed in any group known in vascular plant. It can be assigned to definite position of taxon basing on much fossils record and further studies.  相似文献   

8.
目的检测Hey1与Notch1在非小细胞肺癌组织中的表达,探讨Hey1在非小细胞肺癌中的表达与Notch1的表达、各临床病理特征之间的关系。方法制作组织芯片,采用免疫组织化学染色检测Notch1和Hey1在246例非小细胞肺癌组织及相应117例癌旁正常肺组织中的表达,应用SPSS 21.0进行统计分析。结果 Notch1在肺鳞癌、肺腺癌和癌旁正常肺组织的阳性率分别为78.8%,28.9%和30.8%,Hey1在肺鳞癌、肺腺癌和癌旁正常肺组织中的阳性率分别为79.7%,23.4%和33.3%;肺鳞癌患者Notch1阳性表达与TNM分期和淋巴结转移情况呈正相关;肺鳞癌患者Hey1阳性表达与TNM分期呈正相关,与肿瘤分化程度呈负相关;Spearman相关分析显示,肺鳞癌和肺腺癌组织中Notch1表达与Hey1表达具有显著的正相关关系。结论 Hey1和Notch1与肺鳞癌的恶性程度密切相关,可能是肺鳞癌发生、发展的重要参与因子。  相似文献   

9.
Dynamics of Contention. Dou McAdam, Sidney G. Tarrow, and Charles Tilly. Cambridge: Cambridge University Press, 2001. 387 pp.  相似文献   

10.
Suppose it is desired to determine whether there is an association between any pair of p random variables. A common approach is to test H0 : R = I, where R is the usual population correlation matrix. A closely related approach is to test H0 : Rpb = I, where Rpb is the matrix of percentage bend correlations. In so far as type I errors are a concern, at a minimum any test of H0 should have a type I error probability close to the nominal level when all pairs of random variables are independent. Currently, the Gupta-Rathie method is relatively successful at controlling the probability of a type I error when testing H0: R = I, but as illustrated in this paper, it can fail when sampling from nonnormal distributions. The main goal in this paper is to describe a new test of H0: Rpb = I that continues to give reasonable control over the probability of a type I error in the situations where the Gupta-Rathie method fails. Even under normality, the new method has advantages when the sample size is small relative to p. Moreover, when there is dependence, but all correlations are equal to zero, the new method continues to give good control over the probability of a type I error while the Gupta-Rathie method does not. The paper also reports simulation results on a bootstrap confidence interval for the percentage bend correlation.  相似文献   

11.
Macrolycus is a genus of net‐winged beetles with 69 species distributed in the eastern Palearctic and northernmost part of the Oriental region. The first molecular phylogeny of Macrolycus was produced using an rrnL + tRNA‐Leu + nad1 mtDNA fragment. The major lineages and species limits were identified with morphology and molecular data. We propose that Cerceros is a subgenus of Macrolycus to enable identification of all adult specimens in the genus without DNA sequencing. Two species groups are proposed in Macrolycus s. str. and six in Cerceros. Additionally, twelve Macrolycus species are newly described from China: M. aquilinus, M. baihualingensis, M. bicolor, M. guangxiensis, M. jianfenglingensis, M. kuatunensis, M. lizipingensis, M. parvus, M. phoeniceus, M. rhodoneurus, M. rosaceus and M. sichuanensis. Macrolycus holzschuhi is proposed to be a junior subjective synonym of M. jeanvoinei. The highest diversity of Macrolycus is found in southern China. The species from the main islands of Japan are placed in two species groups: M. excellens is a sister to remaining species of the M. murzini group and the M. flabellatus group is a monophylum of closely related species in a sister position to the M. bicolor group.  相似文献   

12.
Consider a model yt = ft(θ) + Mt, 0 ⩽ tT where θ∈ Θ in an unknown parameter, ft(θ) is a linear predictable process, Mt is a martingale difference, and the nature of E(M2t/ℱt—1) is unknown. This paper presents an estimating procedure for θ based on the asymptotic quasi-likelihood methodology. Conditions under which the asymptotic quasi-likelihood estimate converges to the true parameter θ0 are discussed. This method is applied to several simulated examples, and estimates of the unknown parameter are obtained by means of a two-stage technique. Comparison is made between the estimates obtained via this method and those obtained via the ordinary least squares method. Discussion is provided on the application of the model.  相似文献   

13.
14.
Danforth's short tail (Sd) is a semidominant mutation on mouse chromosome 2 that acts cell autonomously in the notochord and leads to its disintegration, and thus causes severe defects in somite patterning and vertebral column development. The molecular nature of the Sd gene and mutation is unknown, and it is unclear whether Sd is a loss-of-function mutation and the semidominant inheritance of the Sd phenotype is due to haploinsufficiency, or whether Sd represents a gain-of-function mutation in a gene essential for notochord development and maintenance. Here, we report on the genetic interaction between Sd and an insertional mutation called Etl4lacZ, which provides genetic evidence that Sd is a gain-of-function mutation. Etl4lacZ is an enhancer trap insertion, which gives rise to lacZ expression in distinct cell types, including the notochord. In homozygosity, the lacZ insertion leads to abnormal vertebrae in the caudal part of the vertebral column. Etl4lacZ maps approximately 0.75 cM distal to Sd, and in double heterozygotes modifies the Sdphenotype contrarily, depending on the chromosomal configuration of the Sd and Etl4lacZ mutations: when Etl4lacZ is present on the chromosome wild type for Sd (Sd +/+ Etl4lacZ; trans configuration), the Sd phenotype is enhanced, i.e., vertebral malformations extend to more anterior positions and the vertebral body of the axis is further reduced. Conversely, when Etl4lacZ is present on the same chromosome as Sd (Sd Etl4lacZ /+ +; cis configuration), the Sd phenotype is attenuated, i.e., vertebral malformations are confined to more posterior levels, and the dens axis, which is severely reduced or absent in Sd heterozygotes, is restored. The different effect of the Etl4lacZ insertion on Sd, depending on its presence in trans or cis, suggests a direct interaction of the transgene insertion with the Sd gene. Additionally, the attenuation of the Sd phenotype by Etl4lacZ in cis suggests that Sd is a gain-of-function mutation and lends support to the idea that Etl4lacZ is a new allele of Sd. Dev. Genet. 23:86–96, 1998. © 1998 Wiley-Liss, Inc.  相似文献   

15.
The unarmoured dinoflagellate Nusuttodinium aeruginosum retains a kleptochloroplast, which is a transient chloroplast stolen from members of the cryptomonad genus, Chroomonas. Both N. aeruginosum and the closely related N. acidotum have been shown to restrict their diet to a limited number of species of this blue‐green genus of cryptophyte. However, it is still unclear how flexible the predators are with regard to the ingestion and utilization of Chroomonas spp. as a source of kleptochloroplast. To address specificity of cryptomonad in N. aeruginosum, we collected the cells of N. aeruginosum from several ponds in Japan, and analysed the phylogeny of the kleptochloroplasts based on their plastidial 16S rDNA sequences. All sequences obtained in this study were restricted to only one (the subclade 4) of four subclades known to comprise the Chroomonas/Hemiselmis clade. Therefore, N. aeruginosum is specific in its dietary requirements, selecting their prey within the subclade level.  相似文献   

16.
The CAUCHY-PEXIDER functional equation H (x±y)=F(x) G(y) is generalized to the form H ((xc±yc)1/c) = F(x) G(y), c≠0, assuming the function H(x) possesses a measurable majorant on a set of positive measure. The result is used to obtain a characterization of WEIBULL distribution. This functional equation is generalized to functions of vector variables.  相似文献   

17.
Direct Calculation of a Tree Length Using a Distance Matrix   总被引:8,自引:0,他引:8  
Comparative studies of tree-building methods have shown minimum evolution to be in general an accurate criterion for selecting a true tree. To improve the use of this criterion, this paper proposes a method for rapidly and directly calculating a length of a dichotomous tree without having to resort to branch length calculations. This direct calculation (DC) method applies to the complete final topology, giving equal importance to each branch after a dichotomy. According to this method, the tree length S DC is S DC =∑ i j (D ij /2 Bij ) = (∑ i<j D ij 2 Bmax−Bij )/2 Bmax −1 where D ij is the observed distance between taxa i and j, B ij is the number of branches connecting i and j, Bmax is the greatest B ij in the tree, and the powers of two are due to the dichotomy of the tree. This tree length expression may be used as a rapid method for selecting the shortest tree from a set of hypothetical or subobtimal trees. Received: 2 March 2000 / Accepted: 24 March 2000  相似文献   

18.
All known Queensland species of the isopod family Sphaeromatidae, subfamily Sphaeromatinae (= hemibranchs), are discussed. The following new taxa are erected: Calcipila cornuta, gen. nov., sp. nov. ; Cymodoce tribullis, sp. nov. ; Cymodoce bipapilla, sp. nov. ; Paracilicaea aspera, sp. nov. ; Cilicaeopsis glebosa, sp. nov. ; Cilicaeopsis furculata, sp. nov. ; Cilicaea calcarifera, sp. nov. ; Zuzara curtispina, sp. nov. ; Zuzara digitata, sp. nov. ; and Clianella brucei, sp. nov. Exosphaeroma intermedium Baker is transferred to the genus Sphaeroma Latreille. The genus Dynoides Barnard is reviewed and its current synonymy is contested. With several new records, this brings the total number of sphaeromatid species known from Queensland to 49, 24 of which are in the subfamily Sphaeromatinae. A checklist of all sphaeromatid species occurring in Queensland waters is given. From the rest of Australia: Cymodoce tuberculata Haswell is given the replacement name Cymodoce haswelli, nom. nov. ; Cymodoce granulata Miers is made a junior synonym of Cerceis trispinosa (Haswell) (subfamily Dynameninae); Zuzara diadema Leach, Z. dicantha (Milne Edwards) and Z. Integra Haswell are made junior synonyms of Z. semipunctata Leach; Cilicaeopsis dakini Tattersall is tentatively transferred to the genus Paracilicaea Stebbing. The genera discussed are reviewed world-wide and among the non-Australian species: Exosphaeroma papillae Bayliff is transferred to the genus Sphaeroma; Sphaeroma irakiensis Ahmed is made a junior synonym of Sphaeroma annandalei annandalei Stebbing; Cymodoce richardsoniae Nobili is shown to be distinct from Cymodoce truncata Leach; Cymodoce eupyga Nobili is transferred to the genus Paracilicaea; Dynoides amblysinus Pillai, Dynoides castroi Loyola e Silva and Exosphaeroma globicaudum (Dana) are transferred to the genus Clianella Boone; Dynoides brasiliensis (Loyola e Silva; and Sphaeroma savignn Milne Edwards sensu Dana, 1853 are declared to be conspecific with Clianella castroi. The name Sorrentosphaera Verhoeff is made a junior synonym of Dynamene Leach (subfamily Dynameninae.  相似文献   

19.
Canran Liu 《植被学杂志》2001,12(3):411-416
Abstract. The behaviour of five statistics (extensions of Pielou's, Clark and Evansapos;, Pollard's, Johnson & Zimmer's, and Eberhardt's statistics, which are denoted as Pi, Ce, Po, Jz and Eb respectively) that involve the distance from a random point to its jth nearest neighbour were examined against several alternative patterns (lattice‐based regular, inhomogeneous random, and Poisson cluster patterns) through Monte Carlo simulation to test their powers to detect patterns. The powers of all the five statistics increase as distance order j increases against inhomogeneous random pattern. They decrease for Pi and Ce and increase for Po, Jz, and Eb against regular and Poisson cluster patterns. Po, Jz, and Eb can reach high powers with the third or higher order distances in most cases. However, Po is recommended because no extra information is needed, it can reach a high power with the second or third distance even though the sample size is not large in most cases, and the test can be performed with an approximate χ2 distribution associated with it. When a regular pattern is expected, Jz is recommended because it is more sensitive to lattice‐based regular pattern than Po and Eb, especially for the first distance. However, simulation tests should be used because the speed of convergence of Jz to normal distribution is very slow.  相似文献   

20.
Summary A second flowering gene, Sp, which influences sensitivity to photoperiod, is identified in the sweet pea, Lathyrus odoratus L. Genes Sp and Dn h act in a complementary manner to confer the summer-flowering phenotype and a near obligate long day requirement for flowering in the unvernalized state. Mutations sp and Dn i each diminish the response to photoperiod, and genotypes sp Dn h and Sp Dn i confer a spring-flowering phenotype. Response to photoperiod is further reduced in genotype sp Dn i, which flowers only marginally later than the day-neutral or winter-flowering phenotype characterized by genotypes Sp dn and sp dn (gene dn is epistatic to the gene pair Sp/sp). Like Dn i, gene sp reduces basal branching, while a branching gene, here resymbolized b, is shown to delay flowering in certain circumstances. Gene dn largely prevents basal branching in either b or B plants, but dn b plants do produce lateral shoots from the upper nodes, leading to a novel phenotype. The implications of the interactions between genes sp, Dn i, dn and b are discussed with respect to the control of flowering and branching.  相似文献   

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