the main objective in sampling is to select a sample from a population in order to estimate some unknown population parameter, usually a total or a mean of some interesting variable. a simple way to take a sample of size n is to let all the possible samples have the same probability of being selected. this is called simple random sampling and then all units have the same probability of being ch...

determination of uranium in natural water and complex solutions using ion exchange chromatography: a combined procedure using ion exchange chromatography and uv-vis spectrophotometry techniques has been developed to measure uranum in natural water and complex solutions. after conditicing , one hundred milli liters of sample solutions have been passed through an ion exchange column,pachked with ...

after test and review results and analysis of farm data, the following results were obtained. the review examined farms was done and the results obtained in this study was to determine the effectiveness of vaccines hatchpak avinew (frozen) and hatchpak ib h120 with spray in broilers a day in factories incubation and at least,they can be as vaccines avinew and bioral h120 ability to create saf...

cohesion is an indispensable linguistic feature in discourse analysis. lexicald such a differe cohesion and conjunction in particular as two crucial elements to textual cohesion and comprehension has been the focus of a wide range of studies up to now. yet the relationship between the open register and cohesive devices has not been thoroughly investigated in discourse studies. this study concen...

asymmetric membranes are widely used in many industrial membrane separation processes. the major advantage of membrane filtration over the conventional process is its ability to remove a wider spectrum of particles without using any chemicals. hollow fiber configuration offer many advantages over flat-sheet or tubular membranes. the spinning process of hollow fiber may look simple, yet it is te...

previous studies have aimed at testing a hypothesis but the present study is data-first research in which researcher tries to form a theory from data rather than the use of data to test a hypothesis. this study aims at exploring teachers perceptions of the strengths and weaknesses of the current syllabus for college preparatory course. eight experienced teachers were selected to collect data du...

abstract the first purpose of this study was to investigate the effect of consciousness-raising (c-r) activities on learning grammatical structures (simple present tense in this case) by iranian guidance school efl learners. the second one was to investigate the effect of gender on learning the simple present tense through c-r activities and tasks. finally, this study aimed to investigate the ...

the present study was an attempt to conduct a contrastive analysis between general english (ge) and english for specific purposes (esp) texts in terms of cohesion and cohesive devices. to this end, thirty texts from different esp and ge textbooks were randomly selected. then they were analyzed manually to find the frequency of cohesive devices. cohesive devices include reference, substitution, ...

Exclosure is considered as a management method to improve vegetation. This study aimed to evaluate the effects of exclosure on species diversity in Zayanderod dam station in Chadegan, Isfahan. The study area was stratified based on the various management types and slope directions, and samples were collected randomly in each layer. Four perpendicular transects, 500m in length were established a...