Background Bypassing available facilities for childbirth has important implications for maternal health service delivery and human resources within a health system. The results are the additional expenses imposed on the woman and her family, as well as the inefficient use of health system resources. Bypassing often indicates a lack of confidence in the care provided by the facility nearest to t...

Magnetic-free optical isolators are critical components for the realization of integrated systems. The underlying physics passive nonlinear is not solely about breaking Lorentz reciprocity without requiring any external bias. Indeed, one major obstacle to operation Kerr-type was found be so-called dynamic reciprocity, which serious outcome that a backward signal cannot isolated in presence forw...