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in order to examine the multi-species weed competition in corn field an experiment as an interval mapping was carried out at the agricultural research field of ferdowsi university of mashhad during growing season 2009-2010. at 3-4 leafy stages of corn, 20 non-destructive quadrates determine and the density of weeds was counted separately. at the same time, 20 destructive quadrates determine and...

population dynamic parameters of red mullet, mullus barbatus (n=592) caught by trawlers operating in arzew gulf (algeria) in the western mediterranean were studied. samples were collected between february 2013 and january 2014. females ranged from 10.9-23.2 cm in total length and 12-149.2 g in weight whereas males length was comprised between 12.6 and 19.7 cm and weight between 21.3 and 99.9 g....

in this study, liquid-liquid extraction process in a kuhni extraction column was modeled and simulated. a non-equilibrium dynamic model was developed for modeling liquid-liquid extraction processes based on a rate-based model. the model equations are inclusive of partial and ordinary differential equations which were discretized in column height direction. the population balance model was used ...

ibn khaldun has played a major role in the shaping of pre-modern population theories. he has proposed some important issues and perspectives on the interaction of population dynamics and development. thus, this paper attempts to explore ibn khaldun’s demographic perspectives and identify his approach to population and development interrelationship. the results indicate that ibn khaldun has intr...

Available published research on microsimulation tends to focus on the results of policy simulations rather than upon validation of the models and their outputs. Dynamic population microsimulation models, which age an entire population through time for some decades, create particular validation challenges. This article outlines some of the issues that arise when attempting to validate dynamic po...

a field experiment was conducted to study the spatial relationships between weed seed bank and population and their distribution models in sugar beet crop (beta vulgaris) in 2009 at motahari  agricultural research station of karaj. sampling from seed bank before sugar beet drilling and weed population in three stages during the growing season were done using square (50*50 cm) and rectangle (25*...