METHODS. Trained nurse and lay screeners administered the Retinomax Autorefractor (Right Manufacturing, Virginia Beach, VA), SureSight Vision Screener (Welch Allyn, Inc., Skaneateles Falls, NY), crowded Linear Lea Symbols visual acuity (VA) test at 10 ft (Precision Vision, Inc., La Salle, IL), and Stereo Smile II test (Stereo Optical, Inc., Chicago, IL) to 3to 5-year-old Head Start participants...

The paper describes an improvement of the chopper method for elimination of parasitic voltages in a low resistance comparison and measurement procedure. The basic circuit diagram along with a short description of the working principle are presented and the appropriate low resistance comparator prototype was designed and realized. Preliminary examinations confirm the possibility of measuring ext...

background: considering the controversial information regarding the effects of perchlorate on thyroid function of high risk population as neonates, and given the high prevalence rate of thyroid disorders specially congenital hypothyroidism in our region, this study aims to investigate for the frst time in iran, the relationship between drinking groundwater perchlorate and cord blood thyroid hor...