نتایج جستجو برای: stage cluster sampling has been used
تعداد نتایج: 4997066 فیلتر نتایج به سال:
in this project, some new polyaspartimides, (pas)s, have been synthesized form michael addition reaction between new synthetic bismaleimide (bmi) and some aromatic diamines. a characteristic property of this polyaspartimides is a pendent carboxylic group, which introduced to these polymers from new bismaleimide. bismaleimides (bmi) is one of the interesting compounds, which can be self-polymeri...
The use of space by predators in relation to their prey is a poorly understood aspect of predator-prey interactions. Classic theory suggests that predators should focus their efforts on areas of abundant prey, that is, prey hotspots, whereas game-theoretical models of predator and prey movement suggest that the distribution of predators should match that of their prey's resources. If, however, ...
the aim of this study has been to find answers for the following questions: 1. what is the effect of immediate correction on students pronunciation errors? 2. what would be the effect of teaching the more rgular patterns of english pronunciation? 3. is there any significant difference between the two methods of dealing with pronuciation errore, i. e., correction and the teaching of the regular ...
We study the level and severity of asset poverty, the characteristics of asset-poor households, the trends and persistence of asset poverty, and the role of major lifetime events affecting transitions in and out of asset poverty. We find that, contrary to a sharp decline in the official measure of poverty, which is based on income, the asset poverty rate barely changed over the 1984–99 period a...
Demain, A. L. (Merck Sharp & Dohme Research Laboratories, Rahway, N.J.), I. M. Miller, and D. Hendlin. Production of extracellular guanosine-5'-monophosphate by Bacillus subtilis. J. Bacteriol. 88:991-995. 1964.-Wild-type Bacillus subtilis colonies were found to feed purineless mutants. A strain with high feeding capacity was selected for study, with a guanineless mutant of B. subtilis used as ...
We report high resolution simultaneous measurements of electrical conductance and force gradient between two sharp gold tips as their separation is varied from the tunneling distance to atomic-size contact. The use of atomically sharp tips minimizes van der Waals interaction, making it possible to identify the short-range metallic adhesion contribution to the total force.
Cluster analysis is a useful technique in multivariate statistical analysis. Different types of hierarchical cluster analysis and K-means have been used for data analysis in previous studies. However, the K-means algorithm can be improved using some metaheuristics algorithms. In this study, we propose simulated annealing based algorithm for K-means in the clustering analysis which we refer it a...
with the growth of more humanistic approaches towards teaching foreign languages, more emphasis has been put on learners’ feelings, emotions and individual differences. one of the issues in teaching and learning english as a foreign language is demotivation. the purpose of this study was to investigate the relationship between the components of language learning strategies, optimism, duration o...
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