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951.
王贵昌 《信阳师范学院学报(自然科学版)》2018,(2):333-338
表面吸附态活性氧物种如O~*、OH~*等对H_2O、CH_3OH、CH_4、NH_3所含O-H、C-H以及N-H键的活化有着十分重要的作用,其调控行为与催化剂的本身电子结构、氧物种的碱性以及A-H中H原子的酸性等有着非常密切的关系.通过表面吸附氧物种的修饰可以有效地控制A-H键的活化程度,从而达到调控反应的目的.利用40篇文献综述了近些年来理论科学工作者在该方面的研究成果,期望为实验工作提供有价值的理论指导依据. 相似文献
952.
A new species of Aciliini diving beetles, Thermonectus tremouillesi sp. nov., is described on the basis of adult and larval specimens collected in shaded forest ponds in Argentina. The adults are compared with morphologically close species and diagnosed by the following combination of characters: the colour pattern on pronotum and elytra; the sexual sculpture of the female well marked, covering basal fourth to basal half of elytra; the male protibia narrow with dorsal margin slightly prominent; the tergite IX of male with four posterior projections; the median lobe of aedeagus bifid apically; and the parameres bearing a terminal spur. The larvae, for their part, are compared with those of other species of the genus and diagnosed by the colour pattern of the cephalic capsule, the shape of the nasale, the spinulae on the prementum, and several chaetotaxic features. Both adults and larvae are illustrated in detail combining scanning electron microscope images, digital photos and line drawings of selected structures. The habitat of the new species and its associated fauna are briefly described. 相似文献
953.
JianXin Wang XiaoLi Dong XiaoMing Pang YaFei Lü HuaLin Yi XiaoXia Yang Zhong Wang Song Wu RongLing Wu 《科学通报(英文版)》2012,57(21):2711-2720
Triploids,recognized to occur more frequently in natural and experimental populations of many species than previously appreciated,display important economic and biological values.Despite this,however,linkage analysis for triploids has not been well explored.We develop a statistical model for estimating and testing the linkage between molecular markers in a triploid population derived from a tetraploid and diploid parent.The model incorporates one important meiotic feature of tetraploids by which more homologous chromosomes pair with a greater likelihood than less homologous chromosomes.By implementing the EM algorithm within the maximum likelihood framework,the model provides a procedure for simultaneous estimation of the linkage and preferential pairing factor.The model accommodates the segregating patterns of pseudotest markers and intercross markers with different amounts of informativeness.The utility of the model was validated through a real data analysis and simulation studies.The model provides a statistical tool for linkage analysis in a triploid population by taking into account meiotic behavior of tetraploids.Results from the model will help to shed light on the genetic diversity and origin of a polyploid population. 相似文献
954.
《Journal of Natural History》2012,46(16):2073-2083
Two new leafhopper species of the Neotropical genus Acrobelus Stål, 1869 are described and illustrated: A. nessimiani sp. nov. from Peru (Amazonas Department) and A. rakitovi sp. nov. from Ecuador (Orellana Province). The two new species, distinguished from the other Acrobelus species by their remarkably long male subgenital plates and by the fusiform macrosetae present on these plates, seem to be closely related. A key to male specimens of the five known species of Acrobelus is provided. Taxonomic notes on the genus are included. 相似文献
955.
《Journal of Natural History》2012,46(41-42):2543-2555
The existence is reported of rhizoids in specimens of Bowerbankia pustulosa and Bowerbankia citrina collected from different Iberian locations. The structure of these rhizoids differs from that of other fixation structures previously reported in Bowerbankia and redescribed here. Rhizoids in both species are probably homologous with those of Amathia, supporting the close relationship between these two genera. 相似文献
956.
957.
于2013年4~5月对淮河流域沙河水系进行底栖硅藻标本采样,共鉴定出异极藻科硅藻2属18种5变种,其中中国新纪录1种:假尖顶异极藻(Gomphonema pseudoaugur LangeBertalot),对该种的形态特征和生境分布进行了描述.分析了沙河水系异极藻科硅藻的生态分布特点及其对环境的指示作用. 相似文献
958.
Christopher K. Starr 《Journal of Natural History》2017,51(27-28):1589-1592
Data from well-studied taxa are used together with explicit assumptions and estimates of the world fauna to estimate the number of insect species in Trinidad and Tobago. The median estimate of the world fauna is 4.8 million, while the median estimate of Trinidad and Tobago’s share in the world fauna is 4.8%. Accordingly, it is estimated within broad confidence limits that Trinidad and Tobago harbour 230,400 species. The approach used allows for a refinement of this estimate as new or better data become available. 相似文献
959.
《Journal of Natural History》2012,46(3):667-680
The presence of the landhopper Arcitalitrus dorrieni (Hunt) is reported on the island of Colonsay, Inner Hebrides. It is widely distributed there amongst deciduous leaf litter in forested areas but also occurs in bracken litter and scrub grassland. The species is an introduction from Australia, doubtless transported inadvertently among plants brought to the gardens at Colonsay House. It is, however, not restricted to the ornamental plantings but has colonized native woodland. Maximum population density recorded under leaf litter was 680 m2. Amphipods avoid waterlogged or dry situations preferring to burrow in moist soil under litter from deciduous trees. Coniferous woodlands are more sparsely colonized. Rate of spread (minimum) from the original locus is calculated at c. 25 m/year. Arcitalitrus may prefer to eat sycamore leaves (cf. oak, beech). Ovigerous females are reported for May but no evidence exists for a release of young any earlier in the year. Immature amphipods seem to live more covert lives in the soil beneath the superficial litter layer. Eggs are relatively large and few in number. Amphipods may avoid ants but may have a mite living in phoretic or ectoparasitic association. 相似文献
960.
《Journal of Natural History》2012,46(15):1969-1997
Sympatric reed frog species were studied in Gabon (Monts Cristal: Hyperolius mosaicus, H. pardalis, H. tuberculatus) and Kenya (Kakamega Forest: Hyperolius acuticeps, H. cf. cinnamomeoventris, H. kivuensis, H. lateralis, H. viridiflavus). For each taxon, a standardized diagnosis covering 11 aspects of adult and in part tadpole morphology as well as the sequence of a 560 bp fragment of mitochondrial DNA of the 16S ribosomal gene are provided. In addition, behavioural data are given for each species including measurable parameters of advertisement calls. The Monts Cristal Hyperolius species clearly differ in their spatial arrangement through the choice of breeding site. Hyperolius species at the Kakamega Forest share the same breeding sites but in part differ in their activity pattern throughout the year. Advertisement calls of sympatric species in both regions mainly differ in temporal parameters. 相似文献