aims: considering the medical significance of cockroaches as insect vectors of food toxicities, and triggering allergy in respiratory system and skin, this survey was conducted to study the frequency of infestation and their effective factors in shahin shahr, iran. materials & methods: this cross-sectional descriptive study was carried out in 2010 in shahin shahr, isfahan, iran. data gathering ...

proteases are important enzymes that their role in various industries is undeniable. however, keeping enzymes stable during its activity in harsh conditions is so important. in this study, protease enzyme was immobilized on the porous silica particles and its stability in different temperatures and phs was evaluated. first silica particles were aminated by 3-aminopropyltriethoxysilane then the ...

on the basis of a cross-sectional demographic survey that was conducted among the qashqai tribe of southern iran in 1973, the crude birth rate was estimated at 48.2 per thousand per year. the most productive age groups, was 25-29 years. forty-nine, point seven per cent (49.7%) or about one half of the total births occurred among married women aged 20 to 29 years eighty-seven point three per cen...

data envelope analysis (dea) is an approach to estimate the relative efficiency of decision making units (dmus). several studies were conducted in order to prioritize efficient units and some useful models such as cross-efficiency matrix (cem) were presented.  besides, a number of dea models with interval data have been developed and ranking dmus with such data was solved. however, presenting a...

the analysis of cross-correlations is extensively applied for understanding of interconnections in stock markets. variety of methods are used in order to search stock cross-correlations including the random matrix theory (rmt), the principal component analysis (pca) and the hierachical ‎structures.‎ in ‎this work‎, we analyze cross-crrelations between price fluctuations of 20 ‎company ‎stocks‎‎...

background: although there are efforts being underway to control and prevent intestinal parasitic infections (ipis) in ethiopia, they are still endemic and responsible for significant morbidity. the aim of this study was to evaluate the prevalence of ipis and their association with nutritional status among primary school children of delo-mena district, south eastern ethiopia. methods: a cross-s...

the present study sought to investigate the evidence for cross-linguistic transfer in a partial english immersion and non-immersion educational setting. to this end, a total of 145 first, third and fifth graders in a partial english immersion program and 95 students from the same grade levels in a non-immersion program were chosen. six different english and persian tests were administered: the ...

a lab-scale cross flow membrane bioreactor (cf-mbr) was operated to determine the biokinetic coefficients under mlss concentrations of 5000 and 3000 mg/l. the investigation showed that the yield (y), the endogenous decay coefficient (kd), the maximum specific growth rate (μm) and the saturation constant (ks) were 0.276 mg/mg, 0.07 /day, 0.653 /day, and 396.62 mg cod/l respectively for mlss 500...

cross efficiency is a method with the idea of peer evaluation instead of self-evaluation, and is used for evaluation and ranking decision making units (dmus) in data envelopment analysis (dea). unlike most existing dea ranking models which can only rank a subset of dmus, for example non-efficient or extreme efficient dmus, cross efficiency can rank all dmus, even non-extreme ones. however, sinc...

mathematical modeling of supply chain operations has proven to be one of the most complex tasks in the field of operations management and operations research. despite the abundance of several modeling proposals in the literature; for vast majority of them, no effective universal application is conceived. this issue renders the proposed mathematical models inapplicable due largely to the fact th...