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31.
In relation to the need for rapid assessment of the conservation valeu of wetlands and open waters around the Mediterranean, a rapid and simple survey technique covering a broad range of taxa is described. This method was employed in Tunisia, Algeria and Morocco and the possibility of using the data to construct a classification of North African standing waters investigated. It was divided into four data sets—physical, macrophytes, invertebrates and winter counts of waterfowl—and cluster analyses were carried out on these. An analysis of the levels of relationship between all sites, obtained from the different cluster analyses, was then carried out to combine the results and to construct natural classes. The existence of these classes was confirmed by ordination analyses. 相似文献
32.
Juan M. Herrera Christos Noulas Boy Feil Peter Stamp Markus Liedgens 《植物养料与土壤学杂志》2013,176(4):561-571
The nitrogen (N) fertilization of wheat (Triticum aestivum L.) is important for stable and high grain yield. However, the effect of N on root growth and survivorship is poorly understood. The objectives of this study were (1) to determine the effect of varying N availability on the growth and survivorship of roots and (2) to determine whether genotypic variation in N‐related traits are linked to root growth and survivorship. In a two‐year study, two spring wheat cultivars (Albis and Toronit) and an experimental line (L94491) were grown under low (20 kg N ha–1) and high N supply (270 kg N ha–1) in lysimeters equipped with minirhizotrons. The genotypes showed significant differences in N‐related traits: total shoot N content, grain N yield, N harvest index, and rate of decline in flag‐leaf greenness. However, there were relatively weak and inconsistent genotypic effects on the time course of root density, root growth during grain filling, and root survivorship. The level of N supply was the factor that most influenced the establishment, growth, and survivorship of roots; the high N supply, depending on the year and genotype, increased growth and survivorship of roots from 0% to 68% and 24% to 34%, respectively. 相似文献
33.
This paper describes the clinical and pathological features, diagnosis and management of primary intraoral leiomyosarcomas in the oral cavity of four dogs; they involved the gingivae of the rostral maxilla and mandible, the mucosa of the upper lip and the soft palate. Their features are compared with the those of leiomyosarcomas commonly encountered in the gastrointestinal tract of dogs. Two of the dogs responded well to surgical treatment; one died after its airways were obstructed by a large palatal tumour; and the fourth was lost to follow-up after its owners declined treatment. 相似文献
34.
Robb L Marx J Steenkamp G van Heerden WF Pretorius E Boy SC 《Journal of veterinary dentistry》2007,24(2):86-89
Dentin adhesive restorative techniques are regularly used in veterinary dentistry. Knowledge of the microanatomic structure and properties of dentin is essential to ensure success in restorative procedures. The aim of this study was to describe the density and diameter of dentinal tubules in dog canine teeth using recently described standardized scanning electron microscopy techniques. The results showed dentin of dog canine teeth to be more oval-shaped with a higher tubular density and slightly larger tubular diameters compared with human teeth. These features suggest dog canine teeth have less intertubular dentin compared with human teeth, which may theoretically result in lower resin-dentin shear bond strengths. 相似文献
35.
Loss of the caudal maxilla and ventral orbit after tumor resections can have negative functional and esthetic influences on the eye involved. This article reports on a case of a caudal maxillary acanthomatous ameloblastoma involving the ventral orbit that was resected and stabilized with a masseter muscle flap. The masseter muscle flap was generated from the superficial belly of the masseter muscle in order to close a defect in the orbital rim, created by a caudal maxillectomy. None of the published complications such as enophthalmos, excessive lacrimation, globe deviation, or strabismus were noted, 8 months following the procedure. The only clinical sign present at the time of re‐evaluation was mild lacrimation. The authors propose the use of a masseter muscle flap as a viable technique in stabilizing the ventral orbit after caudal maxillectomy and ventral orbitectomy, preventing the complications associated with this surgery. 相似文献
36.
We tested the hypothesis that concentrations of chemical constituents in stream water can be explained by the depth of water flow through soil. Therefore, we measured the concentrations of total organic carbon (TOC), NO3‐N, NH4‐N, dissolved organic nitrogen (DON), P, S, K, Ca, Mg, Na, Al and Mn in rainfall, throughfall, stemflow, litter leachate, mineral soil solution and stream water of three 8–13 ha catchments on steep slopes (1900–2200 m above sea level) of the south Ecuadorian Andes, from April 1998 to April 2003. Peak C (14–22 mg litre?1), N (0.6–0.9 mg litre?1), K (0.5–0.7 mg litre?1), Ca (0.6–1.0 mg litre?1), Mg (0.3–0.5 mg litre?1), Al (110–390 μg litre?1) and Mn (3.9–8.4 μg litre?1) concentrations in stream water were associated with lateral flow (fast near‐surface flow in saturated topsoil) while the greatest P (0.1–0.3 mg litre?1), S (0.3–0.7 mg litre?1) and Na (3.0–6.0 mg litre?1) concentrations occurred during low baseflow conditions. All elements had greater concentrations in the organic layer than in the mineral soil, but only C, N, K, Ca, Mg, Al and Mn were flushed out during lateral‐flow conditions. Phosphorus, S and Na, in contrast, were mainly released by weathering and (re‐)oxidation of sulphides in the subsoil. Baseflow accounted for 32% to 61% of P export, while > 50% of S was exported during intermediate flow conditions (i.e. lateral flow at the depth of several tens of cm in the mineral soil). Near‐surface water flow through C‐ and nutrient‐rich topsoil during rainstorms was the major export pathway for C, N, Al and Mn (contributing > 50% to the total export of these elements). Near‐surface flow also accounted for one‐third of total base metal export. Our results demonstrate that near‐surface flow related to storm events markedly affects the cycling of many nutrients in steep tropical montane forests. 相似文献
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为准确快速地建立小麦-华山新麦草杂交后代的分子标记鉴定方法,利用180条长度为10bp的随机引物R1～R180对小麦-华山新麦草全套(1Ns～7Ns)二体附加系及其亲本华山新麦草和普通小麦7182共9个材料进行了RAPD分析。结果表明,R131在华山新麦草和小麦-华山新麦草2Ns二体附加系中可以扩增出特异条带。将该特异条带回收并测序,发现其全长为1 126 bp,对其进行序列比对分析后设计SCAR引物S131,然后利用S131重新对9份材料进行了SCAR分析。结果显示,S131只在华山新麦草和小麦-华山新麦草2Ns二体附加系中扩增出特异性条带,表明RAPD标记R131已成功转化为可靠、特异的SCAR标记S131。这个新的SCAR标记可用于检测普通小麦背景下华山新麦草2Ns染色体。 相似文献
38.
