it listens for the tags ateached to the sharks and it will drive around and follow the sharks as theyove. what we have here are dummy plugs and these attach to a hydro phone. it's like a mike re microphone but it goes under water. the hydro phones are listening for acoustic category tags and these are things this big that attach to a fish or shark. every two seconds they will ping, ping. >> these robots have been used to shall a for a decade now. they are used to mob monitor temperature and light and all things you want to know to monitor the ocean. we are asking the robots to do one more thing thing. we want them to follow the shark and characterize the enviroment. so we can build a 3-d map of the animal that we are tracking. and we know where the animal is in that 3 h 3-d space. and when the animal does something different is there anas spentanas anas suspectanaspect of their environment that is changing. you have a fishery that is being over fished but how do you know, just like when i was a boy the fishingfish didn't move away. it's a possibility. our ability to understand that is

. >> we swear that we'll drive out all houthies ateach them a lesson they'll never forget. >> houthi fighters reply with gunfire and tear gas. several people were killed. many more injured. paramedics say some of the shoot shooters wore police uniforms, other reports say that those who are meant to be keeping the peace joined the houthies. these forces are said to be loyal to yemen's long-time ruler ali abdullah saleh who was hosted during the up rising and now backs the houthies. people here are no longer sure who they can trust. the houthies started as a small unit fighting for autonomy into a larger force. in september it took over the capital sanaa. president abd rabbuh mansur hadi escaped to aden in the south and it's in the south that most of the fighting is taking place right now. the tribe here says they're protecting their region against the rebels. >> right now the houthies are fanning out across the country. they insist that they're fighting for a fair distribution of wealth for everyone, not just shias or their own community. some people in the south don't believe them an

at the same time question can challenge notions ateachers, but this requires really giving them the instrumentsge their approaches fostering more independent learning. fostering more the potential of each student. girls excel in language subjects. they tend to be much much better at reading than boys and sometimes they are left behind in math and science because teachers and parents concentrate on their relative skills in language subjects rather than what they could achieve in mathematics and science. >>> still to come on the news hour all of the sport. bangladesh move a step closer to a quarter final at the cricket world cup. ♪ digital, mobile, social. visit aljazeera.com. follow @ajam on twitter. and like aljazeera america on facebook for more stories, more access, more conversations. so you don't just stay on top of the news, go deeper and get more perspectives on every issue. al jazeera america. ♪ >>> now it has long been known that the u.s. national security agency has been secretly collecting data from phones and overseas, but increasingly local u.s. police departments are doing the same