multiple sclerosis (ms) is one of the autoimmune diseases with an unknown cause. the aim of this study was to explore the link between air quality and ms relapses in patients who suffer from ms.this time-series study was conducted on patients registered at the iranian multiple sclerosis society in 2011-2012. they were randomly selected from patients lived in tehran in the last five years, and h...

Dynamic behavior of a circular shaft with geometrical nonlinearity and constant spin, subjected to periodic axial load is investigated. The case of parametric combination resonance is studied. Extension of shaft center line is the source of nonlinearity. The shaft has gyroscopic effect and rotary inertia but shear deformation is neglected. The equations of motion are derived by extended Hamilto...

formal structure • Independent of dynamics (grounding problem) • The causal role for dynamics (physical events) difficult to explain • Unclear how symbols get into a cognitive system • Independent level of explanation (res cogitans) • Symbols are manipulated according to syntactic rules, independently of their meaning (on the basis of their shape alone). Physical structure • Structure which aro...