This paper presents the Tact hand-an anthropomorphic, open-source, myoelectric prosthetic hand that was designed for use by people with transradial amputations in developing countries. This hand matches or exceeds the performance of other state-of-the-art myoelectric prosthetic hands, but costs two orders of magnitude less ($250) and is easy to manufacture with a 3D printer and off-the-shelf parts. We describe our design process, evaluate the Tact hand with both qualitative and quantitative measures of performance, and show examples of using this hand to grasp household objects.

It has been suggested that infant-directed speech (IDS) is a special speech register conducive to gaining infants’ attention, eliciting and expressing affect, and teaching infants about the phonology of the ambient language. Certain similarities have been observed between IDS and pet-directed speech (PDS), but until now these have not been systematically studied. In this study IDS, PDS, and adult directed speech (ADS) are compared on acoustic, phonetic, and affective measures. It has been suggested that IDS should be more tuned to a linguistic didactic function than PDS, but that the two should be similar acoustically and affectively. The results show that IDS and PDS are generally different from ADS, but that IDS and PDS do not differ substantially, either acoustically, or phonetically. As the expected difference between IDS and PDS was not obtained, it could be suggested that dependent variables thought to measure the functions of special speech registers may not necessarily do so unequivocally.