the two-spotted spider mite, tetranychus urticae koch (acari: tetranychidae), is an economically important pest of ornamental plant in iran. the population abundance and spatial distribution were studied on five rosa cultivars including maroussia, wendela, elderado, wenedetta, and hot lady during two growing seasons of 2011 and 2012 in greenhouse. the k parameter, index of dispersion, lloyd’s m...

Recent work suggests that Cournot oligopolists competing in a spatial model, with a uniform distribution of consumers, agglomerate in the center of the market. In this paper we analyze the robustness of this result with a general symmetric distribution of consumers and show that if the population density is "too thin" at the center of the market, then Cournot competition does not yield spatial ...

introduction: clinical application of encapsulated radioactive brachytherapy sources has a major role in cancer treatment. in the present research, the effects of different tissue densities on the dose distribution of a 103pd brachytherapy source in a spherical phantom of 50 cm radius have been studied. material and methods: as is well known, absorbed dose in tissue depends to its density, but ...

since density is considered as one of the most important numerical indices to explain quantitative values of a plant community by affecting on many aspects and activity of ecosystem, on the other hand, awareness about plants distribution pattern in environment is an essential preparation for measurement and study of vegetative cover, therefore, in this research determination of density and dist...

The effect of introducing a mass-dependent diffusion rate approximately m(-alpha) in a model of coagulation with single-particle breakup is studied both analytically and numerically. The model with alpha=0 is known to undergo a nonequilibrium phase transition as the mass density in the system is varied from a phase with an exponential distribution of mass to a phase with a power-law distributio...

bionomics of aphis gossypii glover and its predators coccinella septempunctata l. and hippodamia variegata goeze were studied in varamin (tehran province) during 11th may to 5th october 2006 on eggplant crop, with the interaction (density dependence) between the aphid and either of the predators determined. the reliable sample size (number of leaves) with a maximum variation of 6.73% was about ...

background: score worksheets have been extracted for phd candidates in epidemiology, microbiology and parasitology for the academic year of 1386-87. the main objective in this study is the impact and importance of different subjects on the discrimination results of admission. methods: extracted scores from worksheets are analyzed by minitab15 statistical toolbox. the regression values of differ...

we inverse the surface gravity data to recover subsurface 3d density distribution with two strategy. in the first strategy, we assumed wide density model bound for inverting gravity data and in the second strategy, the inversion procedure have been carried out by limited bound density. wediscretize the earth model into rectangular cells of constant andunidentified density. the number of cells i...