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271.
Nonparametric tests for ordered alternatives in randomised block designs based on within block rankings have been proposed by many authors. This note is concerned with the optimality of the choice of so-called regression constants usually considered in such rank tests. Some examples are discussed.  相似文献   
272.
A simple procedure is described for solvolysis of the glycosidic linkages of polysaccharides and related compounds in and by liquid hydrogen fluoride (HF), which does so without destruction of acid-sensitive sugars or formation of reversion products from the released monosaccharides. Following solvolysis, water is added to effect hydrolysis of the resulting glycosyl fluorides. Liberated reducing sugars are determined qualitatively and quantitatively, without derivatization, by high-performance liquid chromatography.  相似文献   
273.
One difficulty in summarising biological survivorship data is that the hazard rates are often neither constant nor increasing with time or decreasing with time in the entire life span. The promising Weibull model does not work here. The paper demonstrates how bath tub shaped quadratic models may be used in such a case. Further, sometimes due to a paucity of data actual lifetimes are not as certainable. It is shown how a concept from queuing theory namely first in first out (FIFO) can be profitably used here. Another nonstandard situation considered is one in which lifespan of the individual entity is too long compared to duration of the experiment. This situation is dealt with, by using ancilliary information. In each case the methodology is illustrated with numerical examples.  相似文献   
274.
Satellite imagery as a tool for monitoring species diversity: an assessment   总被引:11,自引:1,他引:10  
1. A landscape of 5 × 5·5 km in the Karnataka region of the Western Ghats of India was mapped into seven landscape element types, using field identification of types as well as supervised and unsupervised classification of satellite imagery.
2. Plant communities distributed in these landscape element types were surveyed in the field using 246 quadrats of 10 × 10 m, in order to assess whether these types could be distinguished in terms of species composition. All angiosperms excluding grasses, which could not be identified accurately in the field, were recorded for this purpose.
3. Landscape element types identified in the field harboured significantly distinctive sets of species of flowering plants, and were also by and large distinctive in terms of their species richness.
4. Landscape element types could be identified accurately on the basis of supervised classification: the types thus demarcated harboured distinctive sets of flowering plants.
5. Landscape element types coupled to satellite imagery could then be used to organize a programme of monitoring biodiversity.
6. Unsupervised classification of satellite imagery did not permit classification of landscape element types with a high enough level of accuracy. In consequence, the demarcated landscape element types did not harbour significantly distinctive sets of species of flowering plants. Unsupervised classification is therefore not appropriate in a programme of monitoring biodiversity.  相似文献   
275.
Then ignoring the pleadings of the king, she wandered into the sacred grove of Kumara. Her mind bewildered by the curse of her Guru, she failed to notice this transgression into an area forbidden to women. No sooner did she enter, than she was transformed into a vine clinging to a tree at the boundary of the grove. Kalidasa in Vikramorvasiyam (c. 300 A.D.)  相似文献   
276.
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