>> we have the potential during our lifetime, in the next 10 to 30 years, to slay water and energy shortage, hunger, healthcare, educational issues, where we can create a world of abundance, where we can meet the basic needs of every man, woman and child on this planet. >> woodruff: we examine the clean-up efforts in the gulf of mexico two years after the largest oil spill in u.s. history. >> brown: plus, mark shields and david brooks analyze the week's news. >> woodruff: that's all ahead on tonight's newshour. major funding for the pbs newshour has been provided by: bnsf railway. >> citi. supporting progress for 200 years. at&t the william and flora hewlett foundation, working to solve social and environmental problems at home and around the world. >> and with the ongoing support of these institutions and foundations. and... >> this program was made possible by the corporation for public broadcasting. and by contributions to your pbs station from viewers like you. thank you. >> woodruff: several more secret service careers are ending amid a scandal involving allegations of prostitution and a presidential trip. ray suarez has the story. >> suarez: with new details unfolding all week about just what happened during the president's trip to the summit of the americas, the associated press is reporting the secret service has placed another employee newly implicated in the scandal on leave. officials tell the a.p. that two more agents are resigning today, while another has been fired, bringing to six the secret service employees forced out so far. for secret service agents, it's been a week of disclosures culminating in the news that more will lose their jobs. they were among 11 agents recalled from this hotel in cartagena, colombia, last week on allegations they used prostitutes they met at a local strip club. "the washington post" today identified two of the three agents ousted earlier this week in the scandal. it turned out one of them, david chaney, had posted a picture on facebook of his time protecting republican vice presidential nominee sarah palin in 2008. his comment read: "i was really checking her out, if you know what i mean?" palin had her say on fox news last night. >> well, check this out, bodyguard-- you're fired. the president, for one, he better be wary there of when secret service is accompanying his family on vacation. they may be checking out the first lady. >> suarez: but white house press secretary jay carney said today >> suarez: meanwhile, pentagon officials are looking into allegations that 11 service members were involved as well. and in cartagena, u.s. and colombian authorities continue to investigate the club where the americans allegedly picked up as many as 21 prostitutes. for the latest details we turn to julie pace, a white house reporter with the associated press. she traveled to colombia with mr. obama and has been tracking the developments this week from washington. and is the investigation turning up new details-- details that's pulling in these new people under suspension. >> it appears that there are new details emerging from this investigation. already today we've heard from the secret service, through briefings that they are having with lawmakers and federal officials that the number of secret service employees that are being investigating is up from 11 to 12. we heard from the u.s. military today that the number of people that they're investigating in this is up from 10 to 11. so the scope of the investigation continues to widen. the secret service is continuing to brief lawmakers on the hill. they are briefing the white house. we heard that the president today just received a briefing from director mark sullivan, the director of the secret service. so it appears as more people are being implicated in this investigation, that there are new details that the investigators are learning. >> suarez: careers are ending but some people are leaving on their own steam and some are being fired. what's the difference and why is it important. >> it's a small difference but it is important. the people in the agency who are being fired are being fired because the investigators are finding cause. the people who are resigning are perhaps being implicated to some degree. they may be making a choice that for their careers, perhaps for their family that it's best for them to resign. maybe to try to avoid being fired. but as i said, it is an important difference but it is a small difference. >> suarez: with these latest depar tures that have been reported throughout the day by the ap and others, how many people remain yet to learn their fates? are they fighting their dismissal. and what are they basing that fight on, do we know? >> well, where we stand right now is we had three people on wednesday who were forced out of a job. today we're reporting that there are three additional people who are being forced out of their jobs. and with the disclosure that there are 12 people that the secret service is eingt having that means that there are six others at this point, perhaps more, we don't know, that are still being investigated. it remains unclear whether these people are going to be able to hang on to their jobs or whether we're going to see more fires. >> suarez: susan comings of maine, the senator, has asked openly whether there has to have been previous incidents of this kind. she doubted that this could have been the first time these advance teams ever could have behaved in this manner. can we expect that previous trips are now under the same kind of microscope that the colombian trip was? >> it's certainly possible. because this is raising questions about the president's security. that's really what this all comes down to right now. and that means that there are going to be questions not just about what happened in colombia last weekend, but about what happened when the president has traveled overseas many times previously when he has traveled domestically as well. these agents and officers travel with the president everywhere that he goes. so it's a questions that's being asked at the secret service. it's a question that lawmakers certainly are asking, and that the white house, frankly, is asking and all of us in the press corps obviously as well. >> suarez: what is a jump team, who are they and what do they do? >> so a jump team is one of the teams that goes to the place where the president is going to go ahead of him. some of them travel on a support plane. some of them travel on the plane that actually brings the president's limousine. some of the equipment that travels ahead of the president. so they arrive at the site before the president does. you know, the president arrives in colombia on friday. the incident that we're talking about happened wednesday, thursday. so these agents and officers had been on the ground for some time before the president got there. >> suarez: now with the addition of a new service member in this inquirery as well, let's ask a little bit pore about that. are they in a different line of command. is the inquiry being handled internally by the justice department separately from the one that involves the secret service agents? >> well, right now, everybody seems to be saying the secret service has a process happening. the secret service appears to be having a thorough process. so people want to let this process play out right now. you have a lot of talk about whether congress which does have an oversight roll here may have its own congressional investigation. so far what we have heard is everybody wants to let the secret service have their own investigation. there has been some discussion about mark sullivan, the secret service director, calling for an independent review of this investigation. but right now everything that everyone is focus on is what is happening inside the secret service. >> suarez: any more known about this big party itself. today and through the week it's been mentioned that 20 or 21 women were involved and a similar number of men. what you can tell us about that? >> well, right now we do know from some of the lawmakers that have been briefed on capitol hill that there were about 20 to 21 women who were brought back to the hotel. it is not the hotle that the president stayed at. and there are a lot of rumors, a lot of witness accounts that are coming out of colombia right now, associated press reporters on the ground there have been told that the agents whom we believe to be involved in this incident were drinking heavily. there are reports that they were going out to a bar and partying and bringing people back to the hotel. but right now we're trying to really be cautious about a lot of that detail. you have investigators who are down there trying to dig up that information as well. so we do have some rumors coming out of there but we're trying to be cautious about what we are reporting as this investigation unfolds. >> suarez: but that would be the venue that involved not only secret service agents but the service people as well? >> exactly. they stayed in the exact same hotel. and really, you know, the information that we're getting is very specific at this point to the secret service agents that are involved. the military side of this, we're not hearing a lot of details so far. all we hear from the military is that the now 11 service members that are being investigated were staying at the same hotel, as the secret service officers and that they are being investigated for some type of misconduct so that is where a lot of the unknown questions are right now on the military side of things. >> suarez: julie pace of the associated press, thanks for joining us. >> thank you. >> brown: still to come on the newshour: troubling economic signs, here and abroad; a showcase for cutting edge contraptions; the clean-up of the gulf, two years on; and shields and brooks. but first, the other news of the day. here's hari sreenivasan. >> sreenivasan: a florida judge today set bail at $150,000 for george zimmerman, the man accused of shooting an unarmed teenager, trayvon martin. zimmerman appeared at a hearing in sanford, florida. he apologized to martin's parents, who were sitting in the courtroom, as his lawyer looked on. >> i wanted to say i am sorry for its loss of your son. i did not know how old he was. i thought he was a little bit younger than i am. and i did not know if he was armed or not >> sreenivasan: benjamin crump, the attorney for trayvon martin's parents, said they were disappointed by the judge's decision to grant bail. and, he said, they questioned zimmerman's sincerity. >> zimmerman makes this self-serving apology in court, 50 days later. the real george zimmerman and you all have reviewed it, never once said, i'm sorry. why today. >> sreenivasan: it was unclear when zimmerman will be released from jail. as part of the conditions of his bail, he'll be required to wear an electronic monitoring device and he cannot have any firearms. a commercial airliner crashed in pakistan today, and all 127 people on board were feared dead. the jet went down in bad weather as it tried to land at an airport near the capital, islamabad. as night fell, emergency workers searched the wreckage for any sign of life, but the pakistani defense minister said it was unlikely anyone would survive. u.s. officials have confirmed that four american troops died last night in a helicopter crash in afghanistan. they were in a u.s. army blackhawk that went down in helmand province in bad weather. it was en route to the site of a suicide bombing at an afghan police checkpoint. the presidential candidates in france wrapped up their campaigning today ahead of sunday's first-round election. socialist francois hollande is the current front-runner in the ten-candidate field. incumbent nicolas sarkozy has been hurt by high unemployment, but in nice today, he argued his policies kept things from getting even worse. >> look simply across the borders right next to us, to what has happened to countries whose governments have not wanted to make the choices that needed to be made when they needed to be made. is there one frenchmen who wished for france, the current situation in greece, portugal, spain, ireland, iceland? >> the top >> sreenivasan: the top two vote-getters in sunday's voting will meet in a run-off on may 6. in syria, there was more heavy shelling of the embattled city of homs today, leaving a u.n. cease-fire in tatters. government troops blasted away at two rebel-held neighborhoods in the city. a syrian human rights group based in britain said mortar rounds were landing every five minutes in one area. meanwhile, in damascus and elsewhere, thousands of protesters spilled into the streets once again. they braved gunfire from troops to demand that president bashar assad leave office. huge crowds also gathered in cairo, egypt, to protest against the ruling military. last year, tahrir square was the center of the uprising that ousted president mubarak. today's protests aimed at putting pressure on the country's generals to hand over power to civilians. protesters also called for members of the old regime not to run in the upcoming presidential elections. those are some of the day's major stories. now, back to judy. >> woodruff: as world financial leaders meet in washington, questions loom about the stability of the global economy. on wall street, at least, the mood brightened a bit today. the dow jones industrial average gained 65 points to close at 13,029, although the nasdaq fell seven points to close at 3,000. traders pinned their hopes to strong earnings reports from general electric, mcdonald's, and microsoft. but other, more negative news has raised questions about whether economic growth is slowing again. the unemployment report for march showed the smallest number of new jobs created since november. and this week came data showing housing starts have dropped and factory activity has lessened. at the same time, there are questions about the worldwide recovery. christine lagarde, the head of the international monetary fund, or i.m.f., offered this assessment yesterday in washington. >> we are seeing a light recovery blowing in a spring wind, but we're also seeing some very dark clouds on the horizon. >> woodruff: lagarde said those "dark clouds" include high unemployment, slow growth, and higher gas prices. a day earlier, u.s. treasury secretary timothy geithner sounded somewhat more optimistic. >> i think that if you look ahead, the world is still at the early stage of what's going to be a very long period of pretty substantial rates of growth in the emerging world, the most populous parts of the world. >> woodruff: but europe remains a particular source of concern. the debt crisis weighing on spain, italy, and greece still has the capacity to set back the u.s. recovery. today, ahead of weekend meetings in washington, the i.m.f. announced the 20 leading industrial and emerging nations have pledged $430 billion to help deal with europe's problems. meanwhile, nagging questions about where the u.s. economy is headed are clearly affecting the 2012 presidential race. new polls this week indicate the contest has tightened, with economic worries giving republican mitt romney an opening against president obama. >> he points out he did not cause the recession, but he did make it worse. and he said, "well, look, things are getting better," and i sure hope they're getting better. gosh, i hope they're getting better. but that's not because of him, that's in spite of him. >> woodruff: for his part, the president has charged that republican calls for deregulation and tax cuts will help the wealthy and no one else. >> in this country, prosperity doesn't trickle down. and that's why i'm always confused when we keep having the same argument with folks who don't seem to remember how america was built. >> woodruff: both politicians and the public will be watching critical indicators that may foretell not only where the economy is headed, but who will occupy the white house next year. >> brown: now, mining technology to solve the world's problems. newshour economics correspondent paul solman recently traveled to california and filed this report on some innovative thinkers. it's part of his ongoing reporting, "making sense of financial news." >> reporter: on the back lot at 20th century fox, the world of make-believe, and a typical make-believe vision of the future, courtesy of fox ceo jim gianopulos. >> here's a little peek at what's in store for us. >> at wayland industries, it has long been our goal to create artificial intelligence almost indistinguishable from mankind itself. >> reporter: the sci-fi pipe dream of moving pictures for as long as they've existed. but no dream to those assembled here. this wasn't a film industry gathering, but a conference put together by singularity university, a futuristic silicon valley think tank which fosters and showcases high-tech inventions. their goal is to make the world a better place as fast as possible. co-founder peter diamandis. >> these tools that are now in your hands allow us to really take on any challenge. it's about the most efficient use of capital and tools that have ever existed. >> reporter: singularity's mission is to solve humanity's most pressing problems by spurring new technologies in food, water, energy-- supposedly scarce, but with the tinkerings of technology, says diamandis, potentially abundant. >> we have the potential during our lifetime, in the next 10 to 30 years, to slay water and energy shortage, hunger, healthcare, educational issues, where we can create a world of abundance, where we can meet the basic needs of every man, woman and child on this planet. >> reporter: the key, says diamandis, is that tech growth is not linear-- one, two, three, four, five-- but exponential-- one, two, four, eight, 16, or even faster than that. >> the rate of innovation is a function of the total number of people connected and exchanging ideas. it has gone up as population has gone up. it's gone up as people have concentrated in cities. you know, the coffee shop is the location where people exchange and share ideas. now, the global coffee shop is the internet, and the more people connected, the more innovation we have. think about the fact that a masai warrior in the middle of africa today on one of these cell phones has better mobile com than president reagan did 25 years ago. and if they're on google on a smart phone, they've got better access to knowledge than president clinton did 15 years ago. it's extraordinary! >> reporter: but, says high tech entrepreneur carl bass, we haven't seen anything yet. >> within five to 10 years, we will be printing biological structures with actual function. >> reporter: 3-d printing is already a reality-- copying machines that literally copy in three dimensions toys, product prototypes, and now, living things as well. >> there's some fantastic work going on at wake forest where they're using the same technology of 3-d printing, and they've already printed a human kidney. it's not ready for transplant, but i suspect, within five-ten years, it will be. >> reporter: this conference was filled with sci-fi-like eye- openers. the self-driving car has now been okayed in nevada. >> so we can put your hands right here. >> reporter: doctor dan kraft gave me an e.k.g., and with a stent installed, i've had a lot of them, with his cell phone. >> it's just a two-lead e.k.g., it's pretty basic. but i can see the basic things, that your heart is beating regularly, that your q.r. complex looks normal, that you're not having an s.t. elevation, which is associated with chest pain or acute attack. >> reporter: former astronaut dan barry said the day was soon coming when robots would provide all sorts of services, from the workaday to the intimate. >> robot sex is going to be big, it really is. 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