would get the laugh, you know, from the other guys. >> woodruff: all that and more on tonight's pbs newshour. >> major funding for the pbs newshour has been provided by: >> and by the alfred p. sloan foundation. supporting science, technology, and improved economic performance and financial literacy in the 21st century. >> carnegie corporation of new york. supporting innovations in education, democratic engagement, and the advancement of international peace and security. at carnegie.org. >> and with the ongoing support of these institutions >> 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: some of the biggest names in republican politics took on donald trump with growing fervor today. in salt lake city, mitt romney injected himself into the middle of the g.o.p race, just ahead of tonight's candidate debate. >> if we republicans choose donald trump as our nominee, the prospects for a safe and prosperous future are greatly diminished. >> woodruff: with that, the party's 2012 nominee for president joined the campaign to stop trump from becoming this year's standard bearer. >> dishonesty is donald trump's hallmark: he claimed that he had spoken clearly and boldly against going into iraq. wrong, he spoke in favor of invading iraq. he said he saw thousands of muslims in new jersey celebrating 9/11. wrong, he saw no such thing. he imagined it. his is not the temperament of a the kind of stable, thoughtful person we need as leader. his imagination must not be married to real power. >> woodruff: and, romney charged, trump is a "phony" and "fraud" who's taking advantage of the people who support him. >> he's playing the american public for suckers: he gets a free ride to the white house and all we get is a lousy hat. >> woodruff: romney started by saying he is not joining the race. instead, he said he'd vote for whomever has the best chance of beating trump. it was a stark departure from four years ago, when candidate romney welcomed the billionaire's backing. >> it means a great deal to me to have an endorsement by mr. trump. >> woodruff: within hours today, trump answered at a campaign stop in maine. >> look, mitt is a failed candidate. he failed. i backed mitt romney. i backed him. you can see how loyal he is. he was begging for my endorsement. i could have said, "mitt, drop to your knees," and he would have dropped to his knees. he was begging. >> woodruff: the candidate offered a lengthy, personal critique of romney, blasting his losing effort in 2012. >> he's a choke artist. he's an absolute-- and i started hitting him so hard, and people say, "why are you hitting him so hard?" 'cause we cannot take another loss. we can't take another loss. and mitt is indeed a choke artist. he choked like i've never seen anyone choke. >> woodruff: other republican elders weighed in as well. senator john mccain-- the party's 2008 nominee-- said in a statement: "i would also echo the many concerns about mr. trump's uninformed and indeed dangerous statements on national security issues." and some 70-plus republican experts on foreign policy issued a press release pledging to oppose the frontrunner. but one of trump's former rivals and newest supporters-- new jersey governor chris christie-- dismissed the criticism. he noted he's telling trump not to bolt the party, if he's denied the nomination. >> i have urged him not to leave i've urged him not to do that because i don't think that's a constructive way to go about it and he knows that. >> woodruff: all of this, just hours before trump and his remaining rivals-- ted cruz, marco rubio and john kasich face off again-- in a "fox news" debate in detroit. meanwhile, on the democratic side, underdog bernie sanders took new aim today at hillary clinton and her stance on trade, in lansing, michigan. >> she has supported nafta. i opposed nafta. she has supported permanent normal trade relations with china. i vigorously opposed p.m.r with china. she supported permanent trade relations with vietnam. i opposed that. >> woodruff: clinton stayed off the trail today, but "the washington post" reported a new turn in the f.b.i investigation of her handling of e-mail as secretary of state. it said bryan pagliano-- a former state department staffer who set up her private server-- has been granted federal immunity for his cooperation. clinton has acknowledged it was a mistake to use a private server, but has insisted nothing she received or sent was classified at the time. we'll dig further into today's republican fireworks after the news summary. in the day's other news, both apple and the f.b.i picked up allies today in their legal fight over encryption. there was word that google, facebook, and microsoft will oppose efforts to make apple unlock an iphone. it was used by syed farook in the mass shootings in san bernardino, california. at the same time, relatives of six of the victims filed a brief supporting the f.b.i position. the state of florida is ready to re-instate the death penalty. state lawmakers voted today to replace a law that the u.s. supreme court struck down in january. the old law required a simple majority of jurors to recommend a death sentence. the new one says at least ten of the 12 jurors must agree. from the united nations today, hopeful words on syria. a special envoy declared that a cease-fire is mostly holding after six days. in geneva, staffan de mistura said the truce is fragile, but has "greatly reduced" the violence. >> this is good news for many syrian people. unfortunately, we have to admit like in every cessation of hostilities or ceasefire, and in particular in this one, there are still a number of places where fighting has continued. including parts of hama, homs, latakia, and damascus. >> woodruff: at the same time, amnesty international charged russian and syrian government forces are deliberately targeting hospitals in and around aleppo. it said that amounts to war crimes. north korea has answered a new round of u.n. sanctions by firing half a dozen short-ranged projectiles into the sea. south korea's military says they were fired today near the eastern town of wonsan and flew less than 100 miles. later, the north announced its leader-- kim jong un-- has ordered the military to be ready to fire nuclear weapons, at any time. european leaders sounded increasingly desperate today, to deal with the mounting migrant crisis in greece. nearly 32,000 people are stranded, and largely blocked from moving deeper into the continent. james mates of "independent television news," is there on the ground. >> reporter: don't come to greece, they've been told. don't believe the smugglers, you won't get any further. but still they come. 600 more pouring onto the keys in the port of pireaus this morning. but for these new arrivals, things have changed. no longer are they being waved through on their journey north. for many now, a tent on the dockside is the end of the road. the main ferry terminal has been home to several hured for more than a week now. many young children for whom the longed-for passage to germany may never happen. this is what happens when you try and block a human tide as it flows northwards. just a week or so ago all of these people would have moved on across the macedonian border and towards northern europe. now, well, they're struck here. >> it's obvious that greece cannot do it alone. it was never a greek problem. it was always a european and a global problem. you cannot expect one country to share this big responsibility. >> reporter: senior e.u. officials are in athens today trying to reassure the greeks they're not alone. but the words are aimed at those still thinking of traveling. >> do not come to europe. do not believe the smugglers. do not risk your lives and your money. it is all for nothing. >> reporter: but for those already here, greece may no longer be a transit country. in athens' picturesque squares, many hundreds now sleep in the open, they can't move on, they won't go back. but like zohreg gasam and her four sisters from afghanistan, they've found no welcome. >> we are tonight sleeping there and we not have... yes, blankets, yes. the winter was really cool. >> reporter: there was once a warm welcome for refugees when they came off the boats here, but that was when they were able to move on through. now the burden seems to be falling on greeks alone. and patience and tolerance are becoming harder to find. >> woodruff: the migrant crisis will be the main subject at a european union summit on monday. back in this country, oregon is set to become the first state to eliminate coal from its energy supply by law. the state legislature gave final approval yesterday to the move. it takes full effect by 2030. governor kate brown has indicated she'll sign the bill. wall street made some modest progress today. the dow jones industrial average gained 44 points to close near 16,944. the nasdaq rose four points. and the s&p 500 added nearly seven. and president obama says he'll do something few presidents have done: stay in washington after he leaves office. he said today in milwaukee that he wants sasha-- his younger daughter-- to finish high school before moving. she's now in the ninth grade. still to come on the newshour: two leading republican voices on mitt romney and the feverish efforts to stop donald trump, mosquitoes that fight the virus they spread, the horrifying ways isis is using child soldiers, and much more. >> woodruff: the deep divides among republicans were on full public display today with donald trump at the center of attention. we explore the rifts now with: michael leavitt, former republican governor of utah and stephen moore, an economist at freedomworks, a conservative political group. gentlemen, welcome to both of you. governor leavitt, to you first, we know you know governor romney well. this is almost unpress sent in american politics for the former standard bearer to be going after the current frontrunner like this. four years ago, mitt romney praised donald trump, he begged for his endorsement, according to mr. trump. what changed? >> well, i have the benefit of having actually been there, and i can tell you that the way donald trump described it is simply not accurate. i think governor romney graciously received his endorsement. but i think it would be valuable for me to at least provide a bit of personal context here. i think what we have seen is a personal statement on governor romney's part. i think we've all had a brother or a sister or a close friend we care about who's about to make a very serious mistake that will have bad consequences and we watch it happening and there's a point at which we just simply say i have to say something or i'm not going to feel good about myself. i think mitt romney feels that way about the country, and this was a statement of his own views of how important it is that this not be made in the context of an emotional state that i think we all understand would produce bad consequences. >> woodruff: but governor leavitt, we saw mitt romney said he wasn't there to announce his own candidacy but didn't rule it out, either. is he wait tock called on? we notice he didn't endorse any of the other candidates in the race. >> he says privately to me the same things he says publicly and that is he is not a candidate and doesn't intend to be a candidate. i think this was, as i suggested, a desire to express his views at a time on a matter that he feels deeply about and about a country he cares deeply about and a party he cares deeply about. >> woodruff: stephen moore, what was your reaction to governor romney's statement? >> hi, judy. let me say i don't have a horse in this race. i like mitt romney. i like, actually, ted cruz and donald trump. so i'm not necessarily in favor of one over the other, but i will say this -- by the way, i did support mitt romney when he ran for politics. i think what mitt romney did, with all due respect, is totally disgraceful. i am so ashamed of him as a republican to go after the republican frontrunner, the person very likely to be the republican nominee and basically to say he's dishonest, a phony, to call his voters, the millions and millions of middle class, blue collar workers whom donald trump has brought into the party, which is one thing i love about donald trump as a republican, he's bringing all these people into the party, to call them sukers, i am outraged by it. i actually think the american people and a lot of the republican voters are outraged about it, too. i think this will help donald trump because it makes the point that he is representing the kind of middle-class, blue-collar voters who haven't seen a pay raise in ten years and, you know, the establishment republicans are totally against him and they will do anything they can to stop him. one last pint, if i may, judy, you know, i'm a conservative republican, and i have kind of held my nose and i have, you know, worked for bob dole to win and mitt romney, even though i had serious disagreements with them, because the other establishment said you conservatives have to get behind the candidate. well, now the establishment, now they don't like the candidate and they're saying they're not going to get behind him and, governor, i think that's duplicitous. >> woodruff: governor, what about that? could what governor romney did today backfire in what he said about the people who support the, what, a third or more to havtohave -- third or more of te republican electorate who support donald trump? >> i think there will be people who react that way in the same way when we tell a brother, systemser or friend that is involved in some emotional thing that has them charged up and they're about to make a big mistake, say i'm going to do this because you said that about it. i think mitt romney believes this, and he did not want this to go forward without having made this statement. >> woodruff: but do you see how voters could take this as an insult, if you will, and are you worried democrats will use what he said against donald trump in the fall if donald trump is the nominee? >> well, the democrats have a lot they can use if mr. trump is in fact the nominee. this is a personal statement. he's not running to be a candidate. he's not running for president. he is saying what he believes h is important for the american people to know about donald trump and he is calling the question. he called the question on his tax returns and said, release them so we can see, and if he doesn't, that's all the proof that's necessary. you might recall governor romney went through this himself and i think he concluded it was a mistake for him not to have done it sooner and in a way that answered the questions. he's saying the same thing to donald trump and has questions that i think many other people share. >> woodruff: stephen moore, you said a minute ago you think this could end up helping donald trump. but what about the other efforts? we hear big donors in the republican party are trying to raise money to help whether marco rubio, ted cruz, what about those sneforts. >> well, they're out there. i mean, this is the republican establishment and the millionaires and billionaires of the party think they can buy this election. again, i disagree with donald trump, judy, on a lot of things. i disagree with him fervently on immigration and trade. i am pro immigration and pro trade republican like the governor, and the idea is we're not going to let the voters speak and i think the republican establishment is insulting to the people who go out to these things. i have been to some of these donald trump rallies, judy, and it is amazing the people who turn out. they are bikers, carpenters and they're soccer moms and they're veterans and people care fervently about this country. i just am very reluctant -- i hate to see them diese dissed be republican establishment. donald trump is going to be the nominee and these insults are going to come back and haunt our nominee in november. >> woodruff: very quickly, could you each support donald trump if he ends up being the nominee of the republican president, governor leavitt? >> i think we all want a republican to win the presidency and think it's deeply important that, in fact, it happens and i think that's why mitt romney spoke as well. >> i would certainly, judy, support any of these republicans over hillary clinton. if donald trump is the nominee, he'll win 35 states. he'll win new york. i disagree with follows. he brings tens of millions of new voters into the republican party. >> woodruff: we'll leave it there. >> governor romney obviously disagrees with stephen. >> woodruff: all right, we did get that sense today from his news conference. stephen moore, governor michael leavitt, thank you both. >> thank you. >> woodruff: with the outbreak of the zika virus growing across the americas, scientists are working on new ways to try to stop its spread by targeting mosquitoes. one idea centers on altering mosquitoes to declare war on other mosquitoes. science correspondent miles o'brien has our report. it's part of his series of stories that he's filed from brazil on zika. >> reporter: the most deadly animals on earth may have finally met their match-- and the enemy is them. this is the scene every morning in piracicaba, brazil where the mosquito borne zika virus is raging, along with a long- running outbreak of dengue fever. scientists hit the road, releasing swarms of genetically modified mosquitoes that carry a d.n.a time bomb. they are killer mosquitoes. >> we are in the colony room. this is where you want to have females happy, healthy, and things like that. >> reporter: these mosquitoes are created by a british company called oxitec. karla tepedino runs the supply line. >> this is the biggest mosquito factory in the whole world we are producing two million of male mosquitoes per week. >> reporter: you could say it's "in-gene-ious." oxitec technicians insert a synthetic gene into mosquito eggs that causes them to create too many proteins. it's a fatal disease. while they are still in the lab, they're given an antidote that keeps the disease at bay. once they are released, they find a female and breed. but their offspring inherit the gene that causes the fatal disease. with no antidotes in the wild, they die not long after they are hatched before they can breed. >> the beauty this technique is that it can reach the mosquitoes where no other technique can find it. we are using mosquitoes to fight themselves. >> reporter: it appears to be working. and here's how they know: in addition to the killer gene, they add one that's a special marker. only the genetically modified mosquitoes will glow under a special light. this way they can track the mosquito population. they say 90% of the insects in this area now carry the fatal flaw. >> as the health secretary of piracicaba has stated last year they had 133 cases of dengue this year only one in the area that we are treating. >> reporter: mosquitoes killing mosquitoes. it may sound too good to be true, and despite more than a decade of work, it remains unclear if this can have lasting impact on a bigger scale. it's a high tech twist in the long difficult war to stop the spread of diseases carried by the mosquito species called aedes aegypti. we've been battling the same enemy for generations. >> notice the white tipped palps, the triangular white spots on the abdomen, the white leg bands, and the white flyer shaped design on the thorax. these are characteristic of the adult aegypti mosquito. >> reporter: aegypti is blamed for spreading zika virus, as well as dengue, west nile and yellow fever. combined, the diseases infect hundreds of millions of people a year, causing a host of maladies and birth defects killing several million. but with zika there is growing concern here that other species are guilty as well. in this government lab in recife, brazil they are working to develop a test that can tell if a mosquito is carrying zika virus. right now, no one knows for certain how common it is, or in which species. marcelo paiva is a molecular entomologist. you know, when compare this to dengue and other viruses, we don't know much about zika, do we? >> we have no idea, actually. this is totally new. >> reporter: so it's virgin science? >> it is yeah, i would say we were in a dark field, no light at end of tunnel, now we're trying to clarify things. >> reporter: as they try to solve this complex puzzle, his boss-- entomologist constancia ayres-- is trying to prove a theory that would have huge, global implications-- that another mosquito species called culex quinqufasciatus could also be a so-called vector for zika. culex is 20 times more abundant here in brazil, and is also much more common than aedis aegypti in north america and europe. >> reporter: the two breeds behave very differently. culex bites at night while aegypti prefers the day. culex breeds in dirty water, aegypti likes her water clean. this would dramatically up the ante for traditional mosquito control techniques. >> reporter: so you're going deep all the time. they are infecting culex mosquitoes with zika in the lab, then dissecting them to see how they carry and transmit the virus. the jury is still out on what happens in the real world. it could mean there will be demand for another breed of weaponized mosquito. this not a new battle here in brazil. as a matter of fact, it's a long war. in fact in the 1950s and 1970s they had some success, when they nearly eradicated this mosquito using pesticides, many including d.d.t. but even before d.d.t. was banned though, the mosquitoes developed a resistance to it. so today, with the population of people and mosquitoes so much greater than ever, there really is no realistic way to think about eradication. but scientists all over the world are not ready to surrender. leslie vosshall is a professor of neurogenetics at the rockefeller university in new york. >> so we're trying to figure out why some people are more attractive than others. the diseases start with a mosquito. the mosquito needs to find someone to bite. the more attractive people are bitten more. we want to understand why that is. >> reporter: she and her team performed what they all the "mosquito magnet" study. open the gate, and down the chute they go. turns out: mosquitoes love some of us more than others. so what is the differentiator? >> mosquitoes, especially the ones that are spreading zika, dengue, chikungunya, they love humans over any other animal. so they're cuing into our body odor, the carbon dioxide in our breath. our body heat. and it's the body odor, i think, that distinguishes us from other non-human animals. >> reporter: vosshall and her team are creating "designer" mosquitoes. it's genetic engineering, but a different version from oxitec's self-destructing insects. here they create unique attributes: for example, a bug that can't detect certain odors to try and understand what they are hunting. >> obviously, if we find out what makes a mosquito magnet attractive, then we've understood a big part of what mosquitoes are hunting. then we can interrupt their hunting behavior. >> reporter: in the meantime, all we really have are nets and deet. researchers aren't even sure how the chemical thwarts mosquitoes. can't science do better? >> ultimately, how cool would it be to have a cream that you put on your arm that has a probiotic, right? that makes you demagnetized as a mosquito magnet? >> reporter: but for now, there is little to stop the global health havoc caused by mosquitoes. zika and birth defects are just part of the devastation. the most deadly animal on earth is an easy foe to underestimate and it marches on with impunity. miles o'brien, pbs newshour, recife, brazil. >> woodruff: stay with us. coming up on the newshour": making sense of sexism on wall street, "on my own" public radio host diane rehm's memoir of love and loss, and a soft-spoken musician unleashes her inner beast. but first, a new study provides a disturbing look into the ways isis uses children to fight its battles. hari sreenivasan has our conversation. >> sreenivasan: a new report chronicles the increasing use of children as fighters for the so-called islamic state. the author is based in fort of georgia documented propaganda which praises deceased young fighters as martyrs and shows how the group uses children and youth in suicide operations and found three times as many suicide attacks involving young people in january of this year than last year. for more on the study's findings and what they mean we're joined by one of the report's awe authorize professor mia bloom. unfortunately, child soldiers aren't anything new. how is i.s.i.s. using them differently? >> we started our study with a baseline looking at the literature on child soldiers, looking at biographies and autobiographies of people who had been child soldiers in order to get a sense of what we thought we might expect. so we expected children would be used when they ran out of adults or when they couldn't find adults or the children would be used against civilian targets and we didn't find either of those. instead what we found was children in i.s.i.s. are used alongside the adults, not instead, and, in fact, only 3% of the time were children used against civilian targets, 61% of the time they were going after what we would call hard targets, military, police, militias and the army. >> sreenivasan: so they're doing what the grownups do. >> exactly what the grownups do and in fact we found considerably more suicide bombers than anyone expected. >> sreenivasan: you break it down, 39% are basically car bombs? >> 39% were car bombs. these were vehicle-borne improvised explosive device, but many of the children were wearing what we would call a suicide belt, which is an individual i.e.d. attached to them so they were part of these marauding raids and they'd go into the target, shoot or blow up the i.e.d. or suicide belt at the end of the operation. >> sreenivasan: used to be groups would recruit in secret, that they knew there would be societal backlash. this is the opposite. you're saying in your report i.s.i.s. brags about the fact they're recruiting young kids. >> not only is i.s.i.s. boasting they're using these children but they're using the children also in a way to humiliate the men. what we didn't put into report but will be exploring further is i.s.i.s. is using the children for example in the prison to determines who lives and dies, they're also cruising the children to actually carry out the execution, so they're empowering the children and, by doing so, disempowering the men and this is a way in which they artheyare recruiting the childro basically feel that you will be more than what you are. you won't be a child in a society where you're lesser than, but you will be powerful, you will be a cub and eventually a lion. >> sreenivasan: as you watched through all of these images and videos, you actually point out that almost half these children have smiles on their faces, at least in the propaganda that comes out after. explain that. >> well, one of the things we try to do is we're trying to get a sense of is there any coercion, are the children there voluntarily? so, for example, again, using the baseline of child soldiers, the stereotypical story we know from liberia or uganda is these children are coerced and they're drugged, so they're made to perpetrate an act of horrific violence against members of their own family so they can never go back to their village. we didn't find that with i.s.i.s. we found parents who willingly gave terrorists access to their children. they encouraged the children. one of the images, we see the father saying goodbye to his son. but we also saw a lot of images where the kids are smiling and look they can, like, they are very excited about this future. they even put them in a setting that looks like the garden of eden in order to convey that's where they're headed, they're going to paradise. >> sreenivasan: what kind of age range? under 18 qualifies as a child, but how young were these kids? >> we used age categories based on developmental psychology. some of the kids were as young as 8. we had in age range of 8-12, 13-15, 16-18, and we didn't go above 18 and anyone we knew might be over 18 we didn't include in the study. >> so we have this information. how should this inform our policymaking or our strategy to combat this? >> part of it is we've seen in other instances terrorist groups using very young children. although they didn't brag about it. we did field research in pakistan where the pakistani taliban forcibly recruited very young kids to be suicide bombers. we know there are ways of deradicallizing and deprogramming these children, but it's very involved, it's very expensive, it requires a multi-pronged approach. so part of it is what do we do when soldiers are facing children? we know there are increased levels of p.t.s.d. but we have to figure out ways of not just preventing the children from entering in the first place but what do we do once we find them? >> sreenivasan: you point out some of these children came from other countries far overseas as well. how did they get there? we can understand a 22-year-old figures out a way to get on a bus, a plane. how did these small kids from, say, europe, get in? >> well, what's the really horrific part of the study is we discovered how many parents are bringing their children with them. so among the foreign fighters that are coming from the united kingdom and france, belgium, tunisia, egypt, they're bringing their entire families with them when they go and basically giving the terrorists access to these children when they get there. so we are seeing parents who are basically colluding with the terrorists and allowing their children to die at a very early age. >> sreenivasan: all right, mia bloom. thank you so much. >> thank you so much for having me. >> woodruff: in recent years, there's been more attention on discrimination in places like silicon valley and hollywood. but there's been less attention of late to the continuing problem of harassment and outright sexism in some firms on wall street and the financial industry. companies long have been training workers about appropriate behavior. but lawsuits are still being filed against firms alleging bias and a culture of harassment. a new book casts a harsh spotlight on the way women have been treated over time. economics correspondent paul solman has the story, part of his weekly series, "making sense," which airs every thursday on the newshour. >> stock's going to pluto, man! >> start unloading! >> what? sell? >> dump it now! dump it all! >> reporter: trading floors: for years the cliche has been a menagerie of men. even today only about 15% of traders are female. so, what's it like for a woman? >> one woman i know who used to work with a managing director, if women were walking by in a skirt he would throw himself on the floor, pretend to look up their skirt and they would-- he would get the laugh, you know, from the other guys. >> reporter: former bear stearns managing director maureen sherry had her own trying walk when she worked on wall street. >> when i had come back from my maternity leave, i was still nursing, and kept a breast pump under my desk. one trader would notice and he would start making a mooing sound, and you know, sometimes other herd members would join in! >> reporter: actually mooing!? >> yes. mooing. and one night i was leaving and someone came to tell me that there had been a bet that a young guy would not do a shot of my breast milk, and that he had risen to the challenge. >> do hereby pledge allegiance to the frat. >> reporter: frat-boy antics and overt sexism are vivid features of sherry's new novel, opening belle, based on her experiences on a trading floor in the 1990s, and those of others still in the business. >> on the floor i worked on we had some ex-athletes, new york ranger, we had a knick, we had so-- and, so. people who really, really lived that team mentality. >> reporter: and the competitive edge? >> very competitive. loved to win. yeah. >> reporter: loved to win. loved to compete, loved to win, loved to risk. >> there's no walls, and they're all together, and there's the, the cortisol high of doing trades together, every single day. lots of testosterone, and so, you can see where risk becomes part of the language. >> reporter: and the more risk you take, the greater the high? >> i think that's a proven fact! >> reporter: indeed it is. harvard behavioral economist iris bohnet has studied the research. >> after having experienced the wins-- in particular in men-- testosterone tends to spike. and that makes men even more willing to take risk. that has been coined "the winner's effect," meaning that when we experience a win, that affects how we perceive risks going forward, and become even more risk-loving. interestingly enough, a number of papers now have been written, which couldn't find a winner's effect for women. >> reporter: and that might help explain why women on wall street are paid just 68 cents to a man's dollar and so few make it to or near the top: the males in charge value the winner's effect, even though it exaggerates losses too. >> research does suggest that diverse teams do outperform homogenous teams. >> reporter: and yet, says sherry, women are discriminated against in lots of ways. >> accounts not being given equitably, that's really one way. or, an account being taken away when it wasn't something that you deserved. you have to understand that these men make a really good living, and chances are very high. if they have children, their wife is probably staying home with their children. it is just sort of understood that at a certain point, you're going to just leave to be with your family. >> reporter: it's not just on wall street, says professor bohnet. >> we do know that bias creeps in whenever we take potential into account. we don't naturally expect women to want to climb up the career leader. >> everybody have a good week?! >> reporter: and if you don't think women are likely to climb, then it's a lot easier to treat them "less professionally." >> reporter: i have offered our lovely sales assistant danielle harrison here $10,000 to shave her (bleep) head! >> reporter: maureen sherry knew a female banker who approached a male trader about a promotion. >> she was really vivacious and beautiful, and she went over and she talked to him about it, and he said, "yeah, let's-- we need to sit down and have a proper interview," et cetera. and, he said, "let's meet at this bar." and, she gets there, and she sat down at the table and she said when she put it down and started her prepared interview, he said, "that's what this is about?" and he threw a hotel room key on the-- on the table, and said, "you know, i thought that's why you wanted to meet," or something like to that effect. >> reporter: no shock that, in the last decade, several large financial firms have settled large gender discrimination cases. while smaller suits, usually handled in-house and kept hush- hush, abound. >> one of the people i've spoken with is a lawyer, i said, how many cases in this genre do you have a year? and he said, my firm? about 80. >> reporter: 80!? >> one firm. >> reporter: for years, sherry herself found wall street gratifying, atmosphere notwithstanding. but she left in 2000, when she realized she'd gone about as far as she could go. >> look, when you feel like your career's been determined for you and you're not progressing any further, it's incredibly ungratifying. >> reporter: in other words you hit the glass ceiling. >> yeah. >> reporter: her husband remained in finance but sherry became a writer. her first book, "a children's mystery," was inspired by her new york apartment, where clues to solve an elaborate scavenger hunt are hidden in the walls. there's sylvester mcmonkey mcbean from the sneetches, dr. seuss. >> so you'll see each one is a replica of a room in the apartment. if you put them together you can build out a replica of the whole home. >> reporter: the mother of four had ample distractions, but sherry kept dwelling on her 11 years on wall street. >> if you can't get the story out of your head, and can't let it go, you have to put it to paper. >> reporter: and that's what it was for you? you couldn't let it go? >> i couldn't let it go! it still bothered me. i just wanted to sort of discuss! to let you see through the lens of a woman what it's like to work in a place like that. what it feels like. >> reporter: what it felt like from 1989 to the year 2000. and, apparently, what it still feels a lot like today. pbs newshour economics correspondent paul solman, reporting from new york. >> woodruff: now, a different kind of read: a new memoir captures the grief of losing a spouse and reassessing one's path. jeffrey brown has this latest addition to the newshour bookshelf. already hundreds of syrians have been killed. >> brown: her two-hour daily public radio program produced by wmau in washington, d.c. reaches some two and a half million listeners nationwide. in a book entitled "on my own" she's addressing a more personal an raw topic, the death of her husband john after 54 years of marriage. john was dying owed with parkindowns disease in 2005 and moved into assisted living in 2012. two years later in steady decline he decided to end his life. with doctors legally barred from assisting, his only option was to refuse food, liquids and medication. his death came 10 days later. diane lives with her dog max yand lingering anger over >> i so resented that john was having to go through this long ten-day process to die. he had said ten days earlier he was ready to die and it took him that long. it should not have, i believe, taken him that long. >> brown: you even write, "i rage at a system that would not allow john to be helped to his own death." he knew what he was going through, you two had talked this through, and he just wanted to let it happen. >> he wanted to relinquish life. he did not commit suicide. he wanted to let go of life and be on to his next journey. that helped you in some degree. as hard as it was, you had talked it through. >> even after he said, i'm ready, i'm ready to die, i said to him, sweetheart, are you sure? is this really what you want? and he said, absolutely, i can no longer use my hands, i cannot walk, i cannot feed myself, i cannot do anything for myself, i am ready to die. >> brown: one of the things that wi >> brown: one of the things that i think really resonate with a lot of people is you refer to is capital "g" guilt that you felt along the way as you were moving towards this point. >> of course, of course, of course. how could i not feel guilt? i think every spouse who sees another go into an assisted living facility must experience some of that. it was the guilt i felt. we take rows when we marry for better, for worse, in sickness, in health. >> brown: 54-year marriage >> brown: 54-year marriage, right? which you write about very honestly. you write about periods of joy and partnerships certainly, but also as you say, years of hostility, endless periods of silence. why did you write about that? >> because i believe no marriage is perfect. and yet, so many of us go into marriage or partnership or relationship believing that all is going to be sunny, all is going to be wonderful. i wish, jeff, that i had been more mature because john needed more distance than i did. john needed more quiet time than i did. i love to be with people. john's greatest solace was being alone. >> brown: and in the end, in his last days, was there kind of an understanding reached? >> totally. i mean, there was such closeness in those last three weeks, four weeks. before he died, i would read to >> brown: you know, out of this experience, you have become a much more active advocate i guess for the right to die. that sets you in the middle of a very passionate debate in this country. >> i appreciate both sides. i am arguing not that everyone should feel as i do and ask for death when the time comes. i understand those who would prefer to give and receive palliative of care. totally individual choice. but do not let the law prevent me from making my choice about my own life. >> brown: becoming so public about it also brought you some questions and criticisms from your organization, right? >> exactly. >> brown: whether you are now an advocate or your more traditional role as a journalist, right? >> once i leave the microphone, then i will become as you say, anadvocate. right now, i am advocating for myself. i am not advocating for any organization in particular or any change in any state law in particular. i am advocating for myself. >> brown: so you're now as the book says "on your own." >> yes. >> brown: for the first time in many, many, many years, right? except for maxie. >> except for maxie, who is my constant companion. i talk to maxie. i talk to john and john talks back to me. >> brown: that conversation hasn't stopped, huh? >> it hasn't stopped. i don't think it will stop. and it really helps me. >> brown: you've also announced that you'll stop doing your radio program at the end of this year. and i wonder, are the two related? >> i had decided that since i am currently 79, i will be 80 in september, that 80 will be a good point to step away from the microphone i have held daily for 37 years. it seems to me that there ought to be other, fresher voices-- newer ideas, newer plans-- for a national program like mine and i think i would welcome that change. >> brown: all right, the book is "on my own". diane rehm, thank you so much for letting us come. >> jeff, thank you. >> woodruff: next, another installment of our weekly series brief but spectacular. today, unleashing your inner beast from singer-songwriter thao nguyen of the group "thao and the get down stay down." her latest album, "a man alive," will be released tomorrow and she will be touring cross country starting this month. >> i taught myself how to do this when i was riding the bus to school. ♪ push it. ♪ i did teach myself guitar and various other string instruments. it's a technique called fake iti till you make it. i could give a seminar really. you know my interest in putting on a live show is connecting with people there. i'm a pretty reserved person in my real life in my non-working life, but then when i get on stage it's an opportunity to tap into this beast? ♪ it's the most present i'll ever be in my life. we want people to know that when they come to a show they can come with us we can go somewhere together. to be an asian american woman there's that kind of meekness and timidness and submission that is expected of you. i know that i embody probably the least threatening physical form you could. that's true, that's real. that's, you know, i'm tiny, i understand. i have such love for the audience, but also i'm like i will eat you. i want people to see how little i care about showing that side. when i was growing up i didn't really have freedom of expression. there's no one entirely interested in what i was saying or thinking. the point is that you're fed and that you're given shelter and do well in school. but it wasn't until i got on stage where i realized, it just sort of, i could tap into without even wanting to it just sort of overtook me. now i can tame the beast a little bit enough so that i can only do it for work. to be that open and vulnerable and have crazy eyes and to be sometimes snarling or just screaming. ♪ it's important for me to share that part because you know i think it's healthy for the both of us. i'm thao nguyen and this is my brief but spectacular take on the beast within. >> woodruff: and you can watch other episodes of our brief but spectacular series on our facebook page: facebook.com/newshour. on the newshour online: a new study of the genes behind our hair could help explain why it turns gray, thins or grows between our eyebrows. geneticists at university college london performed a genome-wide study that found 18 regions of interest, ten of which were new to science. read more about their findings, on our home page. all that and more is on our web site, pbs.org/newshour. and that's the newshour for tonight. i'm judy woodruff. join us online and again here tomorrow evening with mark shields and david brooks. for all of us at the pbs newshour, thank you and good night. >> major funding for the pbs newshour has been provided by: ♪ ♪ moving our economy for 160 years. bnsf, the engine that connects us. >> the lemelson foundation. committed to improving lives through invention. in the u.s. and developing countries. on the web at lemelson.org. >> and with the ongoing support of these institutions >> this program was made possible by the corporation for public broadcasting. and by contributions to your pbs station from viewers like you. thank you. captioning sponsored by newshour productions, llc captioned by media access group at wgbh access.wgbh.org ♪ this is "nightly business report" with tyler mathisen and sue herera. back in vogue. house flipping skyrockets to a ten-year high and that has some concern that the real estate market may be getting a tad hot. taxing plans? what hillary clinton and donald trump's tax proposals would mean for your money. energy strain. why pressure is building in a once low-risk corner of the oil market. all that and more tonight on "nightly business report" for a busy thursday, march 3rd. good evening, everybody. welcome. housing has been hot. it's one of the bright spots in our otherwise slow-growing economy. home prices are near record levels. mortgage rates are low and inventory is tight. and those rising prices are bringing back things like bidding wars and