objective: taro (colocasia esculenta l. schott) is a perennial root crop that belongs to araceace family.  it is widely cultivated as a staple food in africa, asia and pacific islands. despite its importance, there is limited information on many aspects of the crop. in order to obtain data that can support improved and sustainable taro production, a field trial was conducted to study the effect...

spiders are the powerful and efficient predators in almost all ecosystems which have effective role in different pest control. the fauna of these arthropods was surveyed during 2005-2009, and their population fluctuations and activities were studied in mazandaran paddy fields in 2005-2006. a total of 53 spider species of 44 genera were collected and identified from paddy fields of mazandaran pr...

To understand why population growth rate is sometimes positive and sometimes negative, ecologists have adopted two main approaches. The most common approach is through the density paradigm by plotting population growth rate against population density. The second approach is through the mechanistic paradigm by plotting population growth rate against the relevant ecological processes affecting th...

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 ...

an application of aerated concret (foam concrete) was experimentally studied. in this study the compressive strength of the proposed concrete was measured the effect of parameters such as aggregate size of broken stone, quantity of cement and various densities were exprementally studies, and the best mixture was select.these prepared mixtures are practically useful to optimize the consumption o...