Noel Tata takes the reins at powerful charity arm of India's Tata group 

NEW DELHI — The half-brother of Ratan Tata was appointed on Friday as the head of the powerful and influential philanthropic arm of India's Tata group, giving him indirect control of the $165 billion conglomerate.   Tata Trusts said Noel Tata, 67, will be its new chairman after the death this week of Ratan Tata, one of India's best-known corporate titans.   The decision followed "many old-timers" in the group wanting him to lead the venture, said one Tata executive, who spoke on condition of anonymity.