Our DD2 (5) has always been spirited. However over the last few months she is constantly being aggressive and jealous of her little sister (DD3 11 months.) She can be very loving and very helpful when she wants but increasingly the only way she is wanting attention is negatively - shouting, refusing to help tidy up etc. If I try to give her one on one time she is great but then much worse once her siblings return. She gets an easy time from her older sibling who is much more laid back. However DD3 is now starting to walk and needing constant supervision which DD2 is getting increasingly jealous of and her behaviour is escalating. We do call her on it and use time out, taking away treats but they seem to have little impact. Any ideas what to do?