495,216 research outputs found
Carbon dioxide reforming of methane with Pt catalysts using microwave dielectric heating
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Stoichiometry patterns in the androdioecious Acer tegmentosum
No full textCITATION: Zhang, X., et al. 2016. Stoichiometry patterns in the androdioecious Acer tegmentosum. Scientific Reports, 6:35022, doi:10.1038/srep35022.The original publication is available at http://www.nature.com/srepENGLISH ABSTRACT: This study evaluates stoichiometry patterns in the androdioecious Acer tegmentosum, a species characterized by a rare reproductive system where males and hermaphrodites coexist. Altogether 31 hermaphrodites and 29 male plants were harvested and samples of leaves, current-year shoots, branches and coarse roots were analyzed to explore gender differences in biomass, C, N and P concentrations of these four components. The nitrogen to phosphorus relationship of each component was examined using SMA estimates. Males had significantly greater amounts of leaf and coarse root dry matter content than hermaphrodites. C, N and P stoichiometry differed significantly between genders, especially in the newly emerging vegetative components (leaves and shoots). Males had higher C/N and C/P ratios in current-year shoots and lower C/P ratios in leaves and branches. Hermaphrodites had higher N/P ratios in the leaves and branches. Males had higher rates of increase in leaf P content than hermaphrodites. This study suggests that stoichiometry patterns may be significantly affected by gender.https://www.nature.com/articles/srep35022Publisher's versio
Diplaziopsidaceae X. C. Zhang & Christenh.
No full textFamily 34. Diplaziopsidaceae X.C.Zhang & Christenh., fam. nov. 3 genera (Diplaziopsis (type of the family), Hemidictyum, Homalosorus). Filices mediocres vel grandes; rhizomatibus crassis, erectis vel decumbentibus; laminis 1-pinnatis, imparipinnatis, pinnis integris, glabris; venis lateralibus utroque costulae latere discretis sed margines versus reticulatim anastomosantibus, areolarum 2–4 series facientibus, sine venulis discretis inclusis; soris secus venas longas prope costulam elongatis, indusio similiter elongato membranaceo obtectis; indusiis plerumque 3–8 mm, interdum ad 1–2 cm longis, arcuatis, allantoideis; numero basico chromosomatum x=31, 40, 41. Genus quod est typus familiae: Diplaziopsis C.Chr. Description: Medium or large ferns, usually in forests near or by streams. Rhizomes decumbent to erect, thick; lamina 1-pinnate, imparipinnate, with pinnae entire, glabrous; veins free on either side of the midrib, but fully anastomosing toward the margins where they form 2 – 4 rows of areoles, without included free veinlets; sori elongate along the long veins close to the midrib, covered by a similarly elongates, membranous indusium; indusia usually 3 – 8 mm, sometimes up to 1 – 2 cm long, arched, sausage-like; spores with wing-like fimbriate and echinate folds, or low perforate plain folds. X=41, 40 or 31. Notes:— Homalosorus pycnocarpos (Spreng.) Pic.Serm. has been transferred to Diplaziopsis by Price (1990). Different from the Asian Diplaziopsis with x=41, the temperate North American Homalosorus pycnocarpos has x=40 and the tropical American genus Hemidictyum marginatum with x=31. Hemidictyum was first shown to be sister to the Aspleniaceae by Schuetpelz & Pryer (2007), but no Diplaziopsis was included in their study. Here, we incorporate new evidence generated in the laboratory of X.-C. Zhang, and place these genera in one family (Wei et al. 2010). The inclusion of Hemidictyum in Diplaziopsidaceae is however still tentative; further studies will have to confirm its placement.Published as part of Christenhusz, Maarten J. M., Zhang, Xian-Chun & Schneider, Harald, 2011, A linear sequence of extant families and genera of lycophytes and ferns, pp. 7-54 in Phytotaxa 19 on page 15, DOI: 10.11646/phytotaxa.19.1.2, http://zenodo.org/record/489399
The evolution of edge vortices underneath a diffuser equipped bluff body
No full textThe edge vortices generated by a diffuser equipped bluff body in ground effect were experimentally studied using a range of methods including particle image velocimetry (PIV), oil flow visualisation andforces. Two edge vortices were observed originating from each side of the diffuser caused by the flow separating off the side off the model and swirling underneath the model. The edge vortices were foundto enhance the downforce generated by the model as the ride height was decreased. At low values of ride height the edge vortices broke down due to the streamwise pressure gradient within the diffuser becoming too severe. This impacted on the forces such that a reduction in downforce and increase in drag was observed. The vortices were generated close the diffuser inlet, evolving from regions of weak recirculation into concentrated vortices which moved inboard and vertically up as the location moved downstream
GeoBalance VBA program
No full textGeoBalance: an Excel VBA program for mass balance calculation in geosciences (by Li X., Zhang C., Almeev R., Holtz F.
Species-habitat associations in a northern temperate forest in China
No full textZhang, C., Zhao, Y., Zhao, X. & Gadow, K. v. 2012. Species-habitat associations in a northern temperate forest in China. Silva Fennica 46(4): 501-519. This contribution identifies species-habitat associations in a temperate forest in north-eastern China, based on the assumption that habitats are spatially autocorrelated and species are spatially aggregated due to limited seed dispersal. The empirical observations were obtained in a large permanent experimental area covering 660 x 320 m. The experimental area was subdivided into four habitat types using multivariate regression tree (MRT) analysis. According to an indicator species analysis, 38 of the 47 studied species were found to be significant indicators of the MRT habitat types. The relationships between species richness and topographic variables were found to be scale-dependent, while the great majority of the species shows distinct habitat-dependence. There are 188 potential species-habitat associations, and 114 of these were significantly positive or negative based on habitat randomization. We identified 139 significant associations using a species randomization. A habitat is not a closed system it may be both, either a sink or a source. Therefore, additional to the randomization, the Poisson Cluster Model (PCM) was applied. PCM considers the spatial autocorrelation of species and habitats, and thus appears to be more realistic than the traditional randomization processes. It identified only 37 associations that were significant. In conclusion, the deviation from the random process, i.e. the high degree of species spatial mingling may be explained by persistent immigration across habitats
GeoBalance VBA program
No full textGeoBalance: a VBA program in Excel for mass balance calculation in geosciences (by Li X., Zhang C., Almeev R., Holtz F.
GeoBalance: an Excel VBA program for mass balance calculation in geosciences
No full textGeoBalance: an Excel VBA program for mass balance calculation in geosciences (Li X., Zhang C., Almeev R., Holtz F., 2020. Geochemistry, 80, 125629)
https://doi.org/10.1016/j.chemer.2020.12562
GeoBalance: an Excel VBA program for mass balance calculation in geosciences
No full textGeoBalance: an Excel VBA program for mass balance calculation in geosciences (Li X., Zhang C., Almeev R., Holtz F., 2020. Geochemistry, 80, 125629)
https://doi.org/10.1016/j.chemer.2020.12562
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