Co-Occurring Plant Species of the West African Critically Endangered Aubregrinia taïensis Heine, in Côte d’Ivoire

The Upper Guinea Forest is subject to heavy deforestation. In this context, many endemic and/or rare plant species are threatened with extinction. This is the case of Aubregrinia taïensis (Aubrév. & Pellegr.) Heine, a critically endangered Sapotaceae species, endemic to Côte d’Ivoire and Ghana. After 3 years of investigation in and around the Tai National Park (TNP) in the West of Côte d’Ivoire, only one individual of this species was located and no sexual reproductive organs (fruits, seeds) were observed. Woody plant species around this individual were inventoried in order to know the species that can co-occur with Aubregrinia taïensis. For that a plot of 30 m of diameter was established around the individual and all of the woody species of this circle were inventoried. Then, the taxonomic diversity, the chorology of the species, the conservation status and their life-form were recorded. A total of 130 woody plant species belonging to 51 families were collected in the site. The most represented families are Euphorbiaceae (12 spp.), Rubiaceae (10 spp.), Annonaceae (7 spp.), Fabaceae, Moraceae, Malvaceae (6 spp. each) while the most represented genera are Diospyros L. (4 spp.), Cola Schott & Endl. and Vitex L. (3 spp.). Species from the Guineo-Congolese Region (GC) are the most abundant (72%). They are followed by West African endemic species (GCW, 19%). Microphanerophytes (mp) are the most abundant and represent more than 40% of the species. Three vulnerable species were found in this plot: Campylospermum amplectens, Placodiscus boya and Trichoscypha cavalliensis. Thus, the preservation of this forest is more than necessary.

1—NITROAKNADININE,A NOVEL NITRO—HASUBANAN ALKALOID FROM STEPHANIA SUTCHUEN ENSIS

A novel hasubanan alkaloid has been isolated along with the known aknadinine from the fresh roots of Stephania sutchenensis.Its structure has been established as 1—nitroaknadinine from detailed spectral studies and confirmed by chemical correlation with aknadinine.The novel alkaloid is the first nitro-hasubanan and also the first example of naturally occurring nitro—alkaloids.

The Characterisation of Residual Strain in Ensis siliqua Shells

This study reports the variation of residual strains within the posterior ventral area of the Ensis siliqua mollusc shell, as determined using glancing incidence synchrotron X-ray diffraction. The outer layer of this structure exhibits a tensile strain, in contrast to a compressive strain observed within the inner layer. Fluctuations in unit cell parameters for the inner layer have been determined, showing that the microscopic prismatic layer of the structure exhibits a compressive strain orientated parallel to the surface of the shell. This is thought to enhance the crack deflection properties of this layer, and aid in resisting catastrophic failure. Further analysis of residual strains has been performed using the same method, throughout several stages of compressive testing of the anterior dorsal region of the shell. This identified no variation in residual strains at various levels of loading, and it is therefore proposed that load may be transferred via the organic matrix of mollusc shell structures. A Raman spectroscopic investigation, comparing whole and powdered shell with non-biogenic aragonite, has shown that residual strains are also present in this analagous material which is devoid of organic content. This indicates that the observed strain is not entirely due to the organic matrix.

Study on genetic diversity of cultivated populations in 4 species of shrimps

Genetic diversity of cultivated populations was investigated using assay of vertical slabpolyacrylamide gel electrophoresis in 4 species of shrimps, which were Penaeus japonicus, Penaeus monodon , Penaeus vannamei and Metapenaeus ensis, The results showed that the mean number of alle-les per locus (A) is 1.3±0.2, 1.3±0.1, 1.3±0.1 and 1.3 ±0.1 respectively; the percentage of polymorphic loci (P0.95) is 12.5, 6.7, 20 and 23.5 respectively; the expected heterozygosity (He) is 0.042±0.034,0.042±0.031, 0.094±0.042 and 0.097±0.047 respectively; and the observed heterozygosity (H0)is 0.029±0.024, 0.028±0.023,0.154±0.082 and 0.150±0.084 respectively. The difference of genetic diversity is obvious in 4 species of shrimps. The degree of genetic diversity is M. ensis > P. vannamei > P. japonicus > P. monodon. In short, the lower level of genetic diversity is estimated in 4 species of shrimps.

Patterns of forest composition and their long term environmental drivers in the tropical dry forest transition zone of southern Africa

Background： Tropical dry forests cover less than 13 % of the world＇s tropical forests and their area and biodiversity are declining. In southern Africa, the major threat is increasing population pressure, while drought caused by climate change is a potential threat in the drier transition zones to shrub land. Monitoring climate change impacts in these transition zones is difficult as there is inadequate information on forest composition to allow disentanglement from other environmental drivers. Methods： This study combined historical and modern forest inventories covering an area of 21,000 km2 in a transition zone in Namibia and Angola to distinguish late succession tree communities, to understand their dependence on site factors, and to detect trends in the forest composition over the last 40 years. Results： The woodlands were dominated by six tree species that represented 84 % of the total basal area and can be referred to as Bdikioea - Pterocarpus woodlands. A boosted regression tree analysis revealed that late succession tree communities are primarily determined by climate and topography. The Schinziophyton rautanenfi and Baikiaea plurijuga communities are common on slightly inclined dune or valley slopes and had the highest basal area （5.5 - 6.2 m^2 ha＆-1）. The Burkea africana - Guibourtia coleosperma and Pterocarpus angolensis - Diafium englerianum communities are typical for the sandy plateaux and have a higher proportion of smaller stems caused by a higher fire frequency. A decrease in overall basal area or a trend of increasing domination by the more drought and cold resilient B. africana community was not confirmed by the historical data, but there were significant decreases in basal area for Ochna pulchra and the valuable fruit tree D. englerianum. Conclusions： The slope communities are more sheltered from fire, frost and drought but are more susceptible to human expansion. The community with the important timber tree P. angolensis can best withstand high fire frequency but shows signs of a higher vulnerability to climate change. Conservation and climate adaptation strategies should include protection of the slope communities through refuges. Follow-up studies are needed on short term dynamics, especially near the edges of the transition zone towards shrub land.

变电站站间联络率研究

目前,国内外关于优化变电站站间联络率从而提高供电可靠性的研究十分有限,针对这一现状,计及110kV变电站电气主接线和设备运行状态,从可靠性的角度出发,在主变压器满足N-1原则的基础上,以系统电量不足指标(ENSI)最小为优化目标,研究变电站出线的最优站间联络比率。应用基于MATLAB的多元线性回归模型推导联络率与变电站主变压器数量、变电站负载率之间的函数关系,建立模型求解,得到了变电站最佳站间联络率。

Evaluation of the value of near infrared(NIR)spectromicroscopy for the analysis of glycyrrizhic acid in licorice

It has been reported that hyperspectral data could be employed to qualitatively elucidate the spatial composition of tablets of Chinese medicinal plants.To gain more insights into this technology,a quantitative profile provided by near infrared(NIR)spectromicroscopy was further studied by determining the glycyrrhizic acid content in licorice,Glycyrrhiza uralensis.Thirty-nine samples from twenty-four different origins were analyzed using NIR spectromicroscopy.Partial least squares,interval partial least square(iPLS),and least squares support vector regression(LS-SVR) methods were used to develop linear and non-linear calibration models,with optimal calibration parameters(number of interval numbers,kernel parameter,etc.) being explored.The root mean square error of prediction(RMSEP) and the coefficient of determination(R^2) of the iPLS model were 0.717 7% and 0.936 1 in the prediction set,respectively.The RMSEP and R^2 of LS-SVR model were 0.515 5%and 0.951 4 in the prediction set,respectively.These results demonstrated that the glycyrrhizic acid content in licorice could barely be analyzed by NIR spectromicroscopy,suggesting that good quality quantitative data are difficult to obtain from microscopic NIR spectra for complicated Chinese medicinal plant materials.