this study investigates the strategies native english and persian speakers employ for expressing gratitude in different situations. the strategies of persian efl learners are also compared with english strategies in order to find the differences that may exist between these two languages. social status and size of imposition of the favor are social variables which are investigated in detail for...

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...

a one dimensional dynamic model for a riser reactor in a fluidized bed catalytic cracking unit (fccu) for gasoil feed has been developed in two distinct conditions, one for industrial fccu and another for fccu using various frequencies of microwave energy spaced at the height of the riser reactor (fccu-mw). in addition, in order to increase the accuracy of component and bulk diffusion, instanta...

abstract in aggregate, active forms of reactive silica with mineral names are sometimes associated with sand and gravel in concrete mixture. alkali hydroxides originated from alkalis in the cement or other resources form an alkaline silica gel with this reactive silica which becomes swallowed and expanded during time causing damage to concrete. there have been growing researches on alkaline r...

to explore the idea the investingation proposed, aimed at finding whether the performances of the population of iranians students studying english in an efl context are consistent in l1 and l2 writing taks and whether there is a cross-linguistic transfer in this respect. in this regard the subjects were instructed to write four compositions-two in english and two in farsi-which consisted of an ...

it is definitely necessary to understand the concept and behavior of causation of life insurance policies and its determinants for insurance managers, regulators, and customers. for insurance managers, the profitability and liquidity of insurers can be increasingly influenced by the number of causation through costs, adverse selection, and cash surrender values. therefore, causation is a materi...

the present study was an attempt to compare the effect of peer metalinguistic corrective feedback on elementary and intermediate efl learners speaking ability to see which level benefits more from this type of feedback. to this end, 117 female efl learners at grade 3, al-zahra high school in kermanshah, iran were non-randomly chosen. the homogeneity of the participants was attained through a pi...

the construct of self-efficacy has received increasing attention in research over the past two decades. many studies have been carried out 1.3 significance of the study this study has pedagogical implications since improving students’ self- efficacy and autonomy is important for promoting actual performance on classroom academic tasks. in academic settings, it has been shown that self-effi...

deployable scissor type structures are composed of the so-called scissor-like elements (sles), which are connected to each other at an intermediate point through a pivotal connection and allow them to be folded into a compact bundle for storage or transport. several sles are connected to each other in order to form units with regular polygonal plan views. the sides and radii of the polygons are...

this thesis basically deals with the well-known notion of the bear-invariant of groups, which is the generalization of the schur multiplier of groups. in chapter two, section 2.1, we present an explicit formula for the bear-invariant of a direct product of cyclic groups with respect to nc, c>1. also in section 2.2, we caculate the baer-invatiant of a nilpotent product of cyclic groups wuth resp...