Wednesday, April 1, 2015

Headlines that could have been dated April 1

Golfers terrified amid hunt for 'disembowelling' bird

Team of pet detectives called in to catch the 6ft South American bird which has taken up residence on a Hertfordshire golf course

"For days, the members of Barkway Park Golf Club have had to pluck up courage to venture out to play, for fear of being attacked by a 6ft bird reputedly capable of disembowelling a man with a flick of its six-inch claws.
But help is now at hand, after a team of professionals were called in to track down and capture the South American creature..."

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Space hopper man caught bouncing through underpass

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German court rules that men can urinate while standing


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Richard Dawkins wants to fight Islamism with erotica.

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Belle de Jour author Brooke Magnanti insists she was a call girl
"Belle de Jour writer Dr Brooke Magnanti goes to court to defend her claims that she worked as prostitute, saying she will "present evidence that I was a sex worker" in unusual libel battle with her former boyfriend Owen Morris"

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See my post from April 2014:

Headlines that could have been dated April 1, from the Telegraph


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Tuesday, March 31, 2015

Making college admissions work better; in today's NY Times

In today's NY Times, several very very short contributions, including one by me....

How to Improve the College Admissions Process

INTRODUCTION

rfdadmissionsAndré da Loba
The Times columnist Frank Bruni’s new book, “Where You Go Is Not Who You’ll Be,” appeals to teenagers and their parents to relax, because the college decision won’t matter as much as they think it will. But as those thin and thick envelopes arrive in mailboxes across the country, don’t colleges and universities share some of the responsibility for the absurd competition?
What can selective colleges and universities do to improve the admissions process?
READ THE DISCUSSION »

DEBATERS

Repeated Games, by Jean-Francois Mertens, Sylvain Sorin, and Shmuel Zamir

Repeated games can last a long time, and it turns out they also take a long time to write about.  But the wait is over for the definitive book that Bob Aumann, in his foreword, notes was fifty years in the making.
Repeated Games, by Jean-François Mertens, Sylvain Sorin, Shmuel Zamir 

Aumann has written a five page, fascinating historical foreword that is well worth reading. Here are a few paragraphs:

"The theory born in the mid to late sixties under the Mathematica-ACDA project started to grow and develop soon thereafter. For many years, I was a frequent visitor at CORE – the Center for Operations Research and Econometrics – founded in the late sixties by Jacques Dreze as a unit of the ancient university of Leuven-Louvain in Belgium. Probably my first visit was in 1968 or ’69, at which time I met the brilliant, flamboyant young mathematician Jean-Francois Mertens (a little reminiscent of John Nash at MIT in the early fifties). One Friday afternoon, Jean-Francois took me in his Alfa-Romeo from Leuven to Brussels, driving at 215 km/hour, never slowing down, never sounding the horn, just blinking his lights – and indeed, the cars in front of him moved out of his way with alacrity. I told him about the formula, in terms of the concavification operator, for the value of an infinitely repeated two-person zero-sum game with one-sided incomplete information – which is the same as the limit of values of the n-times repeated games. He caught on immediately; the whole conversation, including the proof, took something like five or ten minutes. Those conversations – especially the vast array of fascinating, challenging open problems – hooked him; it was like taking a mountain climber to a peak in the foothills of a great mountain range, from where he could see all the beautiful unclimbed peaks. The area became a lifelong obsession with him; he reached the most challenging peaks.

"At about the same time, Shmuel Zamir, a physics student at the Hebrew University, asked to do a math doctorate with me. Though a little skeptical, I was impressed by the young man, and decided to give it a try. I have never regretted that decision; Shmuel became a pillar of modern game theory, responsible for some of the most important results, not to speak of the tasks he has undertaken for the community. One problem treated in his thesis is estimating the error term in the above-mentioned limit of values; his seminal work in that area remains remarkable to this day. When Maschler and I published our Mathematica-ACDA reports in the early nineties, we included postscripts with notes on subsequent developments. The day that our typist came to the description of Zamir’s work, a Jerusalem bus was bombed by a terrorist, resulting in many dead and wounded civilians. By a slip of the pen – no doubt Freudian – she typed “terror term” instead of “error term.” Mike did not catch the slip, but I did, and to put the work in its historical context, purposely refrained from correcting it; it remains in the book to this day.

"After finishing his doctorate, Shmuel – like many of my students – did a postdoctoral stint at CORE. While there, he naturally met up with JeanFrancois, and an immensely fruitful lifelong collaboration ensued. Together they attacked and solved many of the central unsolved problems of Repeated Game theory.

"One of their beautiful results concerns the limit of values of n-times repeated two-person zero-sum games with incomplete information on both sides – like the original repeated Geneva negotiations, where neither the US nor the SU knew how many nuclear weapons the other side held. In the Mathematica-ACDA work, Maschler, Stearns, and I had shown that the infinite repetition of such games need not have a value: the minmax may be strictly greater than the maxmin. Very roughly, that is because, as mentioned above, using information involves revealing it. The minmax is attained when the maximizing player uses his information, thereby revealing it; but the minimizing player refrains from using her information until she has learned the maximizing player’s information, and so can use it, in addition to her own. The maxmin is attained in the opposite situation, when he waits for her. In the infinitely repeated game, no initial segment affects the payoff, so each side waits for the other to use its information; the upshot is that there is no value – no way of playing a “long” repetition optimally, if you don’t know how long it is.

"But in the n-times repeated game, you can’t afford waiting to use your information; the repetition will eventually end, rendering your information useless. Each side must use its information gradually, right from the start, thereby gradually revealing it; simultaneously, each side gradually learns the information revealed by the other, and so can – and does – use it. So it is natural to ask whether the values converge – whether one can speak of the value of a “long” repetition, without saying how long. Mike, Dick, and I did not succeed in answering this question. Mertens and Zamir did: they showed that the values indeed converge. Thus one can speak of the value of a “long” repetition without saying how long, even though one cannot speak of optimal play in such a setting. This result was published in the first issue – Vol. 1, No. 1 – of the International Journal of Game Theory, of which Zamir is now, over forty years later, the editor.

"The Mertens–Zamir team made many other seminal contributions. Perhaps best known is their construction of the complete type space. This is not directly related to repeated games, but rather to all incomplete information situations – it fully justifies John Harsanyi’s ingenious concept of “type” to represent multi-agent incomplete information.

"I vividly remember my first meeting with Sylvain Sorin. It was after giving a seminar on repeated games (of complete information, to the best of my recall) in Paris, sometime in the late seventies, perhaps around 1978 or ’79. There is a picture in my head of standing in front of a grand Paris building, built in the classical style with a row of Greek columns in front, and discussing repeated games with a lanky young French mathematician who actually understood everything I was saying – and more. I don’t remember the contents of the conversation; but the picture is there, in my mind, vividly.

"There followed years and decades of close cooperation between Sylvain, Jean-Francois, Shmuel, and other top Israeli mathematical game theorists...



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(The book seems to be available online for free to members of the Econometric Society, and here is some other information:
Cambridge Books Online http://ebooks.cambridge.org/
Book DOI: http://dx.doi.org/10.1017/CBO9781139343275 )

Monday, March 30, 2015

A first kidney exchange in Argentina

Julio Elias writes:

"yesterday was performed the first kidney exchange in Argentina.
It was a two-way kidney exchange. The four surgeries were performed at Fundacion Favaloro in Buenos Aires, a very well known Hospital and Research Center in Argentina. The 4 patients are in good condition after the surgery.

Even though the kidney exchanges (donacion cruzada) is not legislated in Argentina yet, and not considered in the Law of Transplants (Ley Nacional de Trasplantes), a judge authorized them to do it, after they presented an appeal.

There were some attempts to modify the law in 2012 and 2013 to incorporate the possibility of Kidney Exchanges, but it didn't go through. So, I think that this exchange may help to develop kidney exchanges in Argentina.

This kidney exchange received a lot of attention in the news because one of the recipient was Jorge Lanata, one of the most famous journalist in Argentina.

Fundacion Favaloro, the center where they did the transplants, was founded in 1975 by Rene Favaloro, best known for his pioneering work on coronary artery bypass surgery."
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Here are some articles in Spanish, which Google Translate does a reasonable job of making comprehensible (while showing the limitations that machine translation still labors under)

News in Spanish about First Kidney Exchange in Argentina
-        JorgeLanata fue trasplantado de un riñón en la Fundación Favaloro (Jorge Lanata was transplanted a kidney in the Favaloro Foundation), Diario La Nacion, Argentina, March 29,2015.

-        Enuna operación inédita, Jorge Lanata recibió un trasplante de riñón (In an unprecedented operation, Jorge Lanata received a kidney transplant), Diario Clarin, Argentina, March 28, 2015.

-        ParteMédico del Trasplante Renal con Donantes Vivos Intercambiados (Medical Reports of the Kidney Exchange), Fundacion Favaloro (https://www.fundacionfavaloro.org/ ), Argentina, March 28, 2015.

 
-        A video where the journalist Jorge Lanata explains everything about the transplant exchange some days before the surgery.

Sunday, March 29, 2015

A proliferation of single-center kidney exchanges

Kidney exchange is becoming a very standard part of kidney transplantation in the United States, which is good news. But, as more and more transplant centers gain experience with kidney exchange, a good deal of it is being conducted within single centers: i.e. among the patients at a single hospital.

This is mixed news...since even more transplants can be achieved in thicker markets.

Here are some of the recent, celebratory announcements about exchanges and chains at Yale, in New Haven, and California Pacific Medical Center in San Francisco ...

8 patients, 4 kidney exchanges, all in one day at Yale New Haven Hospital

Members Of Successful 8-Person Organ Exchange Meet, Feel Like One Big Family


THE SCIENCE BEHIND A CRAZY 6-WAY KIDNEY EXCHANGE

Saturday, March 28, 2015

In Canada, Doctors worry how organ donations will be affected by Supreme Court ruling on assisted suicide

Here's the story from the National Post
Doctors worry how organ donations will be affected by Supreme Court ruling on assisted suicide

"As the nation awaits legalized doctor-assisted death, the transplant community is grappling with a potential new source of life-saving organs — offered by patients who have chosen to die.

"Some surgeons say every effort should be made to respect the dying wishes of people seeking assisted death, once the Supreme Court of Canada ruling comes into effect next year, including the desire to donate their organs.

"But the prospect of combining two separate requests — doctor-assisted suicide and organ donation — is creating profound unease for others. Some worry those contemplating assisted suicide might feel a societal pressure to carry through with the act so that others might live, or that it could undermine struggling efforts to increase Canada’s mediocre donor rate.

“Given the controversy and divided opinion regarding physician-assisted suicide in Canada, I don’t think we are anywhere near being ready to procure the organs of patients who might choose this path,” said Dr. Andreas Kramer, medical director of the Southern Alberta Organ and Tissue Donation Program in Calgary.


“I think there is a legitimate possibility that advocating aggressively for this could compromise the trust that the Canadian public has in current organ-donation processes,” Dr. Kramer said.
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"Organ harvesting after doctor-assisted death is already a reality in Belgium, which became the second country in the world, after the Netherlands, to legalize voluntary euthanasia in 2002.

"In 2011, Belgian surgeons reported the first lung transplants using lungs recovered from four donors put to death by lethal injection. All — two patients with multiple sclerosis, one with a neurological disorder and the other a mental illness — explicitly and voluntarily expressed their wish to become an organ donor after their request for euthanasia was granted, the team reported.

“We now have experience with seven lung donors after euthanasia,” Dr. Dirk van Raemdonck, a surgeon from University Hospitals Leuven, told the National Post. “All recipients are doing well.”

Lungs, as well as kidneys and livers, have been retrieved and transplanted from a total of 17 euthanasia donors, Dr. van Raemdonck said. The results will be presented next week at the annual meeting of the Belgian Transplantation Society in Brussels."

Friday, March 27, 2015

Are we nearing a turning point for doctor-assisted suicide/death with dignity?

The NY Times has a thoughtful piece looking back at recent changes, and considering what hasn't changed:  Stigma Around Physician-Assisted Dying Lingers

"Five states, in various forms, countenance doctor-assisted dying. Others are considering it. In California, legislation to permit such assistance is scheduled to receive a hearing this week. A lawsuit in New York that seeks a similar result was filed in State Supreme Court last month by a group of doctors and dying patients. The emotional wallop of these issues is self-evident, and it is captured in the latest installment of Retro Report, a series of video documentaries that explore major news stories of the past — looking back at where we have been to see where we may be headed.
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"Arguments, pro and con, have not changed much over the years. Assisted dying was and is anathema to many religious leaders, notably in the Roman Catholic Church. For the American Medical Association, it remains “fundamentally incompatible with the physician’s role as healer.”
Some opponents express slippery-slope concerns: that certain patients might feel they owe it to their overburdened families to call it quits. That the poor and the uninsured, disproportionately, will have their lives cut short. That medication might be prescribed for the mentally incompetent. That doctors might move too readily to bring an end to those in the throes of depression. “We should address what would give them purpose, not give them a handful of pills,” Dr. Ezekiel Emanuel, a prominent oncologist and medical ethicist, told Retro Report.
But to those in the other camp, the slippery-slope arguments are overwrought. Citing available information from the few jurisdictions where assisted dying is permitted, supporters of “dying with dignity” laws say that those looking for an early exit tend to be relatively well off and well educated. There is no evidence, they say, to suggest that such laws have been used promiscuously by either patients or their doctors. As for the medical association’s ethical judgment, it “focuses too much on the physician, and not enough on the patient,” said Dr. Marcia Angell, a former executive editor of The New England Journal of Medicine. Writing in The New York Review of Books in 2012, Dr. Angell asked, “Why should anyone — the state, the medical profession, or anyone else — presume to tell someone else how much suffering they must endure as their life is ending?”

Thursday, March 26, 2015

Redesigning the Israeli Medical Internship Match

Israel has a new system for allocating medical intern positions. It's quite different from the system in the U.S., in large part because hospitals are passive. Assaf Romm and Avinatan Hassidim are playing a big role in the design of several markets in Israel, and some papers just appeared on this one in the Israel Journal of Health Policy Research:

Original research article   Open Access
Slava Bronfman, Avinatan Hassidim, Arnon Afek, Assaf Romm, Rony Sherberk, Ayal Hassidim, Anda MasslerIsrael Journal of Health Policy Research 2015, 4:6 (20 March 2015)


Commentary   Open Access
Alvin E Roth, Ran I ShorrerIsrael Journal of Health Policy Research 2015, 4:11 (25 March 2015)


Assaf Romm writes:

"Every year about 500 medical students in Israel are assigned to 23 different hospitals in Israel for an internship (in Hebrew this phase is called סטאז') that lasts one year. Unlike the American market, in which both interns have preferences over being hired by different hospitals, and hospitals have preferences over hiring different resident, in Israel the market is one-sided, and hospitals (which are owned by the government) are not allowed to express their preferences. The reason for that is that the Ministry of Health (MoH) does not want the better medical students to do their internships in the big cities (Tel Aviv and Jerusalem) only, but instead prefers to scatter across the country. Then again, students do have diverse preferences because of family issues or other issues, and we would like to accommodate those preferences if possible. There is also the option of being matched as a couple, and in 2014 there were 24 couples in the market.

In the past the MoH employed the random serial dictatorship mechanism (RSD). Ex-post trades (with no monetary transfers) were allowed, which created a black market (with monetary transfers) for internships in Tel-Aviv and other highly demanded places. This led to MoH banning trading positions if one of the positions traded was ranked in the first to fourth places by the intern that received it through RSD.

Last year our team helped in redesigning the mechanism. The change was meant to improve the efficiency of the results, by moving from RSD which is ex-post efficient, to a mechanism which is rank-efficient (see Featherstone C., 2014, working paper). Using surveys we tried to assess interns' "utilities" from being assigned to differently ranked hospitals, and then we were able to maximize a linear program given those weights (while making sure, per the student body's demands, that no student's "utility" goes below her RSD allocation).

The interesting thing from a theory standpoint is that most of the algorithms that we know of and that provide an ordinally-efficient result require Birkhoff-von Neumann (BvN) decomposition. However, when there are couples in the market it can be shown that some matrices cannot be decomposed to a convex combination of valid "permutation" matrices. Furthermore, the problem of determining whether a matrix can be decomposed is NP-complete. We decided to consider algorithms that approximately decompose matrices, i.e., they result in a convex combination of valid matrices, but the sum of the combination is only very similar to the original matrix, and not exactly equal to the original matrix.

We were able to prove a lower bound on the distance between the approximation and the original matrix, and then came up with an approximation algorithm that manages to almost exactly hit this lower-bound. We tested the algorithm on actual data (and bootstrapped data) from recent years and showed it performs very well.

The new algorithm was deployed last year and was since used three times. The responses were very good, and we've also seen (as expected) a major improvement in rank distribution. MoH has agreed to continue running the new mechanism in the coming years. The student body related to the 2015 lottery also voted for continuing with the new mechanism. (We also ran a survey on medical interns that took part in the match, but unfortunately participation was very low.)

This project is summarized in two papers: the first one above in the IJHPR, and this one:


Redesigning the Israeli Medical Internship Match (Noga Alon, Slava Bronfman, Avinatan Hassidim and Assaf Romm) - Intended for Economics and CS audience. Includes detailed introduction about the market, analysis of interns' preferences, the NPC result, the approximation algorithm, and simulations that show performance on preference data."