London, Aug 6 (UNI) Indian athlete Nirmala Sheoran entered the semi-final of the 400m Heats event in the ongoing World Athletics Championships here today. Nirmala while participating in the Heat 5 secured fourth spot clocking 52.1 second, ahead of her were Zoey Clark of Britain at 3rd spot clocking 51.88 second, Patience Okon of Nigeria 51.83 second at second spot, while Quanera Hayes of US clocked 51.43 emerging at top. Today's timing was not her best which she had clocked at Patiala earlier this year. UNI XC NC AE SHK 2000