objective: one of the main cultural issues in universities is relationships between male and female students. due to the adverse consequences of this issue, explaining of the beyond the causes of friendship with opposite-sex, is one of the first steps in planning for youth issues. methods: this qualitative research was conducted based on content analysis. nineteen female university students wer...

the expansion of major cities regardless of the scientific planning principles has led to theemergence of negative urban development impacts in iran such as the degradation of natural resources andvarious forms of pollution. undoubtedly, urban rivers can enhance the ecological value of the earth to anoptimal extent. however, to benefit from these potentials, appropriate planning looks inevitabl...

Feedback from community interactions involving mutualisms are a rarely explored mechanism for generating complex population dynamics. We examined the effects of two linked mutualisms on the population dynamics of a beetle that exhibits outbreak dynamics. One mutualism involves an obligate association between the bark beetle, Dendroctonus frontalis and two mycangial fungi. The second mutualism i...

While elaborate carotenoid-based traits in adult birds may have evolved as honest signals of individual quality in the context of sexual selection or other social interactions, the function of carotenoid-based colours in juveniles is less well understood. We investigated the hypothesis that carotenoid-based nestling colouration has evolved in response to parental preference of intensely coloure...

and methodological developments by recognizing the importance of micro-, meso-, macro-, and cross-scale approaches. The term landscape ecology was coined in 1939 by the German geographer Carl Troll, who was inspired by the spatial patterning of landscapes revealed in aerial photographs and the ecosystem concept developed in 1935 by the British ecologist Arthur Tansley. Troll originally defi ned...

Ecological context generates interspecific variation in mating behavior by imposing differential constraints on the action of sexual selection, but operation of these constraints in nature is not well understood. We used field and laboratory studies to examine the importance of body size and size of sexually dimorphic appendages, the gnathopods, for pairing success in two freshwater amphipod sp...