Derailleur gears a detent or ratchet mechanism which stops the gear lever, and hence the cable and the derailleur, after moving a specific distance with each press or pull. Indexed shifters require re-calibration when cables stretch and parts get damaged or swapped. On racing bicycles, 10-gear rear cassettes appeared in 2000, and 11-gear cassettes appeared in 2009. Most current mountain bicycles have either. Many modern, high-end mountain bikes have begun using entirely one chain ring drivetrains, with the industry constantly pushing the number of rear cogs up and up, as shown by SRAM's Eagle groupsets (1 by 12) and Rotor's recent 1
Word sort have a responsibility to students they serve to identify their needs and implement instructional strategies to scaffold students’ understandings of sounds. Intervention strategies may be necessary in remediating students who cannot correctly identify sounds in isolation on a given opportunity. Programs like Reading Recovery have contemporary phonemic techniques embedded in the program. Also, books and poems may specifically focus on word families and similar sound patterns for children to identify and understand in context. Sound sorts can be integrated through programs, or very inexpensively through teacher-created materials. For example, students can sort pictures by beginning sound, rhyme, or ending sound.