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101.
This study aims to assess the natural and cultivated plant species in 26 Bedouin farms in Saint Katherine Protectorate(SKP),identify their soil and water characteristics,and assess the suitability of these farms for the cultivation of some wild medicinal plants.The farms were selected to represent wide wadis with deep sand and clay deposits,gorge-like wadis covered with rock fragments of different sizes,spot-like oases,and the Al Q'aa Plain.Using TWINSPAN(two-way indicator species analysis)and DCA(detrended correspondence analysis)techniques,the 26 farms were classified into 5 groups(Ⅰ-Ⅴ)based on their floristic composition of wild plants.These groups reflect an elevation gradient among the farms above sea level from a mean of 119 m to a mean of1,865m.A total of 73 wild species were recorded,with47 in groupⅡ(500-1,000 m)and 25 in group V(1,700 m).The common target species were Artemisia judaica,Acacia tortilis subsp.raddiana,Origanum syriacum subsp.sinaicum and Varthemia montana(34.6%-26.9%).The cultivated speciesnumbered 25,with 17 in groupⅡ(500-1,000 m) andⅡin groupⅣ(1,500-1,700 m).The common fruit trees were olive,grape,fig,apple,palm,almond,apricot and pomegranate(73.0%-42.3%).Based on the soil characteristics,13 farms belong to soil class 2that describes good soils with moderate limitations,and 12 belong to soil class 3 that describes moderately good soils,which can be used regularly for crops after proper treatment. 相似文献
102.
Hydraulic conductivity of the granular soils depends on many factors including the soil density and the particle size distribution. For internally unstable soils, the hydraulic conductivity could be changed beyond a critical value of hydraulic gradient. This discussion calls attention to the effect of the internal stability on the hydraulic conductivity, where the internal stability of the soils is assessed and the critical hydraulic gradient is computed using some theoretical methods, and such calculations could be used to plan the experimental tests. 相似文献
103.
A discussion is presented here to the work of Wang and Qiu including some notes about the analysis and the correlations of the results. First, we show that there is no clear relationship between the critical hydraulic gradient and the uniformity coefficient. Also we show that the internal erosion mechanism of soils with bimodal structure is different from that for soils with no bimodal structure. Finally, we emphasis that the anisotropy in the hydraulic conductivity is not related to the uneven compaction only but also to the particle arrangements and connectivity between pores. 相似文献
104.
Divisional morphogenesis in the marine ciliate Anteholosticha manca (Kahl, 1932) Berger, 2003 (Ciliophora: Urostylida) 总被引：1，自引：1，他引：0
LI Liqiong HU Xiaozhong WARREN Alan AL-RASHEID Khaled A S AL-FARRAJ Saleh A SHAO Chen SONG Weibo 《海洋学报(英文版)》2008,27(2):157-163
The cortical development and macronuclear evolution of the marine hypotrichous ciliate Anteholosticha manca, collected from the coastal waters near Qingdao, China, were investigated using the protargol impregnation method. The morphogenesis of A. manca is generally typical for the genus, and can be characterized as the following features ： （ 1 ） in the proter, a new oral primordium is formed on the bottom （beneath the pellicle） of the buccal cavity, disorganization of the parental undulating membranes do not contribute to the formation of this primordium ; （2） FVT-cirral anlagen in both dividers develop independently, and very likely only a few midventral cirri join in the formation of these primordia; （ 3 ） both marginal row and dorsal kinety anlagen develop intrakinetally within the parental structure; （4） at the middle stage, macronuclear segments fuse together to form a single mass as observed in most of its related forms. 相似文献
105.
Geotectonics - Abstract—Mesozoic‒Cenozoic tectonic zoning and its evolution are characterized by analysis of geological data on the Black Sea–Caucasus–Caspian region. The... 相似文献
106.
Temporal species distributions of planktonic protist communities in semi-enclosed mariculture waters and responses to environmental stress 总被引：1，自引：0，他引：1
In order to evaluate the relationships between temporal species succession of planktonic protists and physical-chemical parameters in semi-enclosed mariculture waters, species distributions in response to environmental stress were investigated in a shrimp-farming pond near Qingdao, China during a complete shrimp-culture cycle (May to October 2002). A clear temporal succession in species distribution was found over the complete farming cycle. For example, before the introduction of the shrimp larvae there was low-variability of species distribution in the protist communities whereas during the stages immediately after, there was higher variability in species composition. Multiple linear/logistic regression analyses demonstrate that 12 protist taxa (e.g., Gyrodinium spirale, Teleaulax acuta, Prorocentrum spp. and Mesodinium pupula) were related to the nutrients, in particular ammonia and phosphates, alone or in combination with water temperature. These results suggest that temporal variations in species distribution of planktonic protist communities might be used in assessing water quality of semi-enclosed mariculture waters. 相似文献
107.
In order to clarify the phylogeny and relationships of the most confused hypotrichous ciliates, Holosticha-complex, four closely related holostichids (five populations), Holosticha bradburyae, H. diademata, Anteholosticha sp., and A. manca, were compared and analyzed using ITS2 secondary structures, ITS1-5.8S-ITS2 region and SSrRNA gene sequences. The ITS1-5.8S-ITS2 region sequences of these four species were first sequenced, and they shared sequence identities ranging from 68.0% to 90.1%, while two populations of Anteholosticha sp. differed in three nucleotides (sequence identity 99.8%). There were several minor differences among ITS2 secondary structures of these species, while two populations of Anteholosticha sp. had the identical secondary structure. Phylogenetic trees inferred from the ITS1-5.8S-ITS2 region sequences of stichotrichs using multiple algorithms (Neighbor-Joining, Maximum Parsimony and Bayesian) revealed similar topologies. The results show that:(1) Holosticha bradburyae and H. diademata firmly clustered together with strong bootstrap supports, forming a sister clade with Anteholosticha sp., (2) Anteholosticha appeared to be a paraphyletic assemblage, in which the morphotype A. manca was more closely related to Diaxonella trimarginata than to its congener Anteholosticha sp. Phylogenetic analyses based on the SSrRNA gene and the combined sequences of SSrRNA gene and ITS1-5.8S-ITS2 region revealed the similar relationships between Holosticha and Anteholosticha, nevertheless their positions within the subclass Stichotrichia differed from each other inferred from different genes. 相似文献
108.
109.
One hundred and thirty nine samples have been studied from the Late Campanian–Early Maastrichtian of three deep wells drilled in Jiza’-Qamar Basin, Eastern Yemen to determine the calcareous nannofossil zones and the age of the sediments. Forty-seven calcareous nannofossil species were identified and four biozones were determined in the present study (CC21–CC24). These biozones are assigned to the Late Campanian–Early Maastrichtian ages. Most of the studied species in this work refer to tropical–subtropical environment. The Campanian–Maastrichtian Boundary was determined in Al-Fatk well based on the last occurrence of Eiffelithus eximus and the last occurrences of Uniplanarius sissinghii and Uniplanarius trifidus. 相似文献
110.
Khaled K. Al-Taha Richard T. Snodgrass Michael D. Soo 《International journal of geographical information science》2013,27(1):95-103
Abstract There now exist several microcomputer processing systems which incorporate algorithms and display techniques appropriate for the class of objects known as images. Zooming, histogram equalization, contrast stretching, ratioing, edge enhancement, and filtering are common options used in these systems. In the present discussion a system is proposed for the equivalent processing of general resolution elements (resells), instead of the homogeneous picture elements (pixels) which are found in image processing systems. The resel processing system requires a new, generalized, repertoire of processing algorithms and a high resolution display. A summary is provided of the facilities and procedures required, a computational metaphor using computer spreadsheets is described, and the applicability to censels (census data elements) and to medical data is suggested. 相似文献