introduction acetic acid bacteria are large group of obligate aerobic gram negative bacteria with the ability to oxidize ethanol to acetic acid (1). they are widely distributed in natural habitats and classified in family acetobacteraceae. members of this family are useful in industrial production of vinegar(2). acetic acid bacteria (aab) can use substrates as glucose, ethanol, lactate or glyc...

this ethnographic case study research was carried out in a private school setting in the context of iran. the research tried to explore the analysis and identity construction of a group of learners and teachers along with the content analysis of books on the basis of four types of commodified, political, national and narrative identities. how english language learners and teachers in an informa...

this study investigated the effects of manipulating the cognitive complexity of tasks along +/- few elements and the time limits on l2 learners writing performance. to conduct the study, 60 iranian efl learners with two levels of proficiency, low and high intermediate, were selected and assigned to three groups based on the time devoted to task completion. the participants performed both a simp...

there is less published research about how teachers in efl contexts respond to students who are relatively less mature and less competent l2 writers. while writing researchers have examined various issues concerning peer and teacher response in writing-oriented classes, little research has centered on the effect of collaborative tasks particularly dictogloss on writing skills. output collaborat...

abstract: the present study is an attempt to find out cultural exophoric references in iranian high-school elt textbooks and touch stone series to compare the frequency of occurrence of such references in these books. the purpose is to find out which of the series of the books under investigation impose a greater referential burden on efl learners as far as their reading comprehension of the ...

the following null hypothesis was proposed: h : there is no significant difference between the use of semantically or communicatively translates scientific texts. to test the null hypothesis, a number of procedures were taken first, two passages were selected form soyrcebooks of food and nutrition industry and gardening deciplines. each, in turn, was following by a number of comprehension quest...

one of the applications of nanotechnology is use of carbon nanotubes for the targeted delivery of drug molecules. to demonstrate the physical and chemical properties of biomolecules and identify new material of drug properties, the interaction of carbon nanotubes (cnts) with biomolecules is a subject of many investigations. cnts is a synthetic compound with extraordinary mechanical, thermal, el...

the purpose of this study was to investigate the effect of task repetition on accuracy of iranian efl learners ’speaking ability. in order to achieve this purpose, a null hypothesis was developed: there is no statistically significant difference between accuracy speaking ability in iranian efl learners by use of task repetition. ; of course i should mention that, beside this null hypothesis, an...

for any educational program to be successful, many factors work hand in hand. based on pervious efl studies, teachers and learners are the keys to gain achievement. granted the fact that explicit and implicit practice plays a key role in education, knowledge of it can help teachers facilitate students’ vocabulary learning. this study investigated to determine the contribution of explicit and i...

in this study, a simple, rapid and selective method was developed for the determination of dexamethasone. the proposed method is based on inhibitory effect of dexamethasone on the oxidation of orange-g by bromate in sulfuric acid media. the reaction was followed spectrophotometrically at 478.5 nm (?max). under optimum experimental conditions, (72.6 ?mol l-1 of orange-g, 0.76 mol l-1 of h2so4, 0...