This case study describes the iterative process used to develop a virtual coaching program for out-of-school-time (OST) educators, particularly those who work in afterschool and library settings. The program, called ACRES (Afterschool Coaching Reflective Educators STEM), design-based implementation research (DBIR) approach consider issues related scale-up. Afterschool settings are complex syste...

A patchy model for the spatial spread of West Nile virus is formulated and analyzed. The basic reproduction number is calculated and com- pared for different long-range dispersal patterns of birds, and simulations are carried out to demonstrate discontinuous or jump spatial spread of the virus when the birds' long-range dispersal dominates the nearest neighborhood interaction and diffusion of m...

let $g$ be a finite group‎. ‎we say that $g$ has emph{spread} r if for any set of distinct non-trivial elements of $g$ $x:={x_1,ldots‎, ‎x_r}subset g^{#}$ there exists an element $yin g$ with the property that $langle x_i,yrangle=g$ for every $1leq ileq r$‎. ‎we say $g$ has emph{exact spread} $r$ if $g$ has spread $r$ but not $r+1$‎. ‎the spreads of finite simple groups and their decorations ha...