p. walter.ed by mutual of america designing can cut of myselfed, individual and group retirement products. that's why we are your retirement company. additional support is provided by -- and by, the corporation for public broadcasting and by contributions to your pbs station from viewers like you. thank you. [ speaking spanish ] [ cheering ] [ speaking spanish ] many of us are trying to find ways to build a more sustainable world for future generations. we're concerned that our planet's well being isn't as secure as it once seemed. but, on every continent, there are new environmentalists who are committed to change. whether it's an individual, a small group, or a grassroots organization, they have made personal sacrifices that most of us couldn't even imagine. man: so no matter where the wind blows,

p. walter. corporate funding provided by mutual of america. designing customized, individual and group retirement products. that's why we're your retirement company. additional support is provided by -- and by the corporation for public broadcasting and contributions to your pbs station from viewers like you. thank you. from the tish wnet studios at lincoln center in new york, hari . >>> renewed violence in eastern ukraine days after diplomats reached international agreement in geneva to defuse the crisis. five people were killed including three pro-russian separatists during a shoot-out at a checkpoint the separatists had set up. russia accused ukraine of failing to protect russian speakers in the area. russian president putin acknowledged the possibility of russian military intervention in the region. during a television interview, when asked whether moscow would press armed pro-russian separatists in eastern ukraine to pull back, the russian ambassador to the united states called for the disarming of ukrainian militias in the western part o

p. walter.orporate funding is provided by mutual of america. designing customized, individual and group retirement products. that's why we're your retirement company. additional support is provided by: and by the corporation for public broadcasting. and by contributions to your pbs station from viewers like you. thank you. >>> from the tish wnet studios in lincoln, new york. >> good evening, thanks for joining us. there is a potentially significant development in the search for malaysian 777 that went missing four weeks ago today, with 239 people on board. britain's channel 4 news has our report. >> reporter: this is the chinese patrol ship, the high shohio ohn 01. it picked up a pulse signal last night a frequency of 41.5 kilohertz, used by black boxes. its location was here, just north of where previous i couldn't say search efforts were concentrated and about 1800 kilometers from perth. >> if, and it's a big if, this is the ping from the black box recorder, it means the search area has gone t

p. walter. and provided by mutual of america. that's why we're your retirement company. additional l support is provided by -- and by the corporation for public broadcasting and by contributions to your pbs stations from viewers like you. from new york. >>> good evening. thanks for joining us. ukraine's national security council held an emergency session tonight after pro russian activists seized new buildings earlier in the day. the interior minister promised what he called a very tough response. they were armed with pistols and rifles and seize add police head kaurs in an eastern ukraine can city. there were hundreds of pistols and ammunition stored at the police head quarters. in a nearby city, they also seized the police head quarters. protestors have occupied a government building there for nearly a week. eastern ukraine has a large russian speaking population. >> there has been another poison gas attack in syria. an amateur video posted online shows men and children crowded into a hospital room, some apparently having difficulty breathing. they say the attack occur

p. walter.rporate funding provided by mutual of america, designing customized, individual and group retirement products. that's why we're your retirement company. additional support provided by -- and by contributions from viewers like you. from lincoln center in new york. >> good evening, thanks for joining us, after a meeting between defense secretary chuck hagel and his polish counterpart, the united states has reportedly agreed to send 150 ground troops to poland for militarywúv exercises. this as part ofz to the crisis in ukraine. poland is west of ukraine. the united states will help poland boost air defenses. word of the deal was made public in "the washington post." the ukrainian foreign minister said that ukraine will not move this easter weekend against pro-russian sep rattists who seized ukrainian government buildings two weeks ago. yesterday he warned what he called more concrete actions against them next week. the armed separatists have refused to leave, despite the deal calling on

p. walter, corporate funding is provided by mutual of america. designing customized individual and group retirement products. that's why we're your retirement company. additional support is provided by -- and by the corporation for public broadcasting. and by -- and by contributions to your pbs station from viewers like you. thank you. [applause] >> did you know it's possible to make your heart ten years younger, regardless of your body composition, genetics, or age? and as you follow this plan, you'll feel healthier, trimmer, fitter, sexier, mentally sharper, and better than you have in a decade. >> narrator: dr. steven masley is board-certified physician, nutritionist, longevity researcher, and award-winning educator, honored as a fellow by the american heart association. >> your food choices, they make a huge difference, not just on your cholesterol profile; they impact the function of your arteries themselves. >> narrator: he is a chef trained at the four seasons and has created delicious, healthy recipes as part of his program to transform h

p. walters. corporate funding is provided by miechual of america, designing customized, individual, and group retirement products. that's why we're your retirement company. additional support is provided by -- and by the corporation for public broadcasting. and by contributions to your pbs station from viewers like you. thank you. sethi: this week on "quest"... sea otters combating climate change... sizemore: to see that change almost overnight was amazing. sethi: ...cars fueled by hydrogen... holloway: i was promised flying cars when i was a kid. this is as close as it's going to get. sethi: ...and scientists trying to build a more resilient forest. pecore: some of the best old-growth stands that we have are in the menominee tribal lands. announcer: major funding for "quest" is provided by the national science foundation. sethi: known as "science on a sphere," giant digital globes just like this one

p shawn kane, secretary ray lahood with us. thank you for being with us. stay with us for developments in the g.m. plan. in washington, i'm ray suarez. >>> welcome to al jazeera america. i'm del walters. these are your stories we're following for you. earthquake in chile, the president of the country traveling to get a first hand look at the damage. >>> the head of gm facing more tough questions. >>> and a tornado touches down in minnesota on monday. more severe weather in the forecast. ♪ >>> we begin in