A class of equations describing the dynamics of two prey sharing a common predator are considered. Even though the boundary and internal dynamics can exhibit oscillatory behavior, it is shown these equations are permanent if only if they admit a positive equilibrium. Going beyond permanence, a subclass of equations are constructed that are almost surely permanent but not permanent; there exists...

infant mortality and morbidity present important challenges to those concerned with community health. we did this research to study epidemiology of diseases of infancy in city of tehran. during 15 days, of 6395 deliveries in tehran hospitals a cohort of 6267 live births entered this study. follow up data were gathered in 1st, 3rd, 6th and 12th months of birth. in this period, 5382 occurrence of...

The machine to be designed and developed with a view to resolve one ofthe irksome problems of this institute has been facing every year. This institute issurrounded by vast non- fertile land area of about 200 acres, which becomes widelyoccupied by numerous breads of bushes and shrubs during post-rainy season. Due tothis unwanted proliferation of such verdant institute gets abysmal look and that...