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...

fluorescence chemical sensors for the highly sensitive and selective determination of pb2+ , hg2+, co2+ and fe3+ ions in aqueous solutions are described. the ion sensing system was prepared by incorporating lipophilic ligand (l) as a neutral ion-selective fluoroionophore in the plasticized pvc membrane containing sodium tetraphenylborate or potasium tetrakis (p-chlorophenyl) borate as a liphoph...

abstract the present study was an attempt to investigate the effect of critical thinking on writing ability of 60 iranian intermediate efl learners studying at chenar language institute in khuzestan, iran. to this end, the participants of the study were selected based on their performance in an pet test, a cornell critical thinking test form x and a pre-test of writing. the participants un...

over the past decades a number of approaches have been applied for forecasting mortality. in 1992, a new method for long-run forecast of the level and age pattern of mortality was published by lee and carter. this method was welcomed by many authors so it was extended through a wider class of generalized, parametric and nonlinear model. this model represents one of the most influential recent d...

?it is of utmost priority for an experienced teacher to train the mind of the students, and enable them to think critically and correctly. the most important question here is that how to develop such a crucial ability? this study examines a new way to the development of critical thinking utilizing critical discourse analytical tools. to attain this goal, two classes of senior english la...

the following null hypothesis was proposed: there is no significant difference between the efl students listening comprehension development receiving pictorial cues and those receiving no cuse. to test the null hypothesis, 52 male and femal freshmen students of medicine studing at iran university of medical scinces were randomly selected from a total population of 72 students. to ensure that th...

abstract: research purpose: the purpose of this research is to identify academic databases assessment factors and criteria at law and political science majors. the necessity of this research is to distinguish academic databases assessment factors and criteria and to identify the most important ones and rank them in order to select an appropriate database according to students’ and faculty memb...

the current study aimed at investigating the relationship between motivation and test preparation strategies (tpss) used by iranian pre-university students in their preparation period for the university entrance exam (uee). due to the importance of uee in iran, this study also attempted to show its impact on these two important variables. to this end, 100 pre-university students in an iranian p...

the study of air infiltration into the buildings is important from several perspectives that may be noted to energy and design of hvac systems, indoor air quality and thermal comfort and design of smoke control systems. given the importance of this issue, an experimental and numerical study of air infiltration through conventional doors and windows has been explored in iran. to this end, at fir...