Tethered headsets are physically connected to the laptop or computer. It is a much more complex system that gives an ultimate VR experience. The VR headset for iPhones works pretty well with iPhone, giving the user an awesome virtual reality experience.
DHA (docosahexaenoic acid) is an omega-3 fatty acid often recommended to women during pregnancy. Thought to protect against a number of pregnancy-related complications, DHA is also said to promote the health of the developing child.
If formula containing DHA and ARA is indeed found to be helpful, its benefits would be most clear in premature infants. Babies that are born early are at risk of DHA deficiency, and it's been found that low levels of DHA in their blood is linked with poorer health outcomes.