This is a survey on known results and open problems about closed aspherical manifolds, i.e., connected closed manifolds whose universal coverings are contractible. Many examples come from certain kinds of non-positive curvature conditions. The property aspherical, which is a purely homotopy theoretical condition, has many striking implications about the geometry and analysis of the manifold or ...

background: protecting islamic values are of great importance for every person as well as every organization. respecting hijab by university students is considered as one of the best examples. this study intends to evaluate the attitude of female students about hijab in health faculty of isfahan university of medical sciences in 2009. methods: 315 female students were selected. data was collect...

Cooperative and gradual covering are two new methods for developing covering location models. In this paper, a cooperative maximal covering location–allocation model is developed (CMCLAP). In addition, both cooperative and gradual covering concepts are applied to the maximal covering location simultaneously (CGMCLP). Then, we develop an integrated form of a cooperative gradual maximal covering ...