Posts Tagged Science

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Our FoldIt Paper is out in PNAS!

Algorithm discovery by protein folding game players

Abstract:

AlgorithmsFoldit is a multiplayer online game in which players collaborate and compete to create accurate protein structure models. For specific hard problems, Foldit player solutions can in some cases outperform state-of-the-art computational methods. However, very little is known about how collaborative gameplay produces these results and whether Foldit player strategies can be formalized and structured so that they can be used by computers. To determine whether high performing player strategies could be collectively codified, we augmented the Foldit gameplay mechanics with tools for players to encode their folding strategies as “recipes” and to share their recipes with other players, who are able to further modify and redistribute them. Here we describe the rapid social evolution of player-developed folding algorithms that took place in the year following the introduction of these tools. Players developed over 5,400 different recipes, both by creating new algorithms and by modifying and recombining successful recipes developed by other players. The most successful recipes rapidly spread through the Foldit player population, and two of the recipes became particularly dominant. Examination of the algorithms encoded in these two recipes revealed a striking similarity to an unpublished algorithm developed by scientists over the same period. Benchmark calculations show that the new algorithm independently discovered by scientists and by Foldit players outperforms previously published methods. Thus, online scientific game frameworks have the potential not only to solve hard scientific problems, but also to discover and formalize effective new strategies and algorithms.

Fulltext at PNAS (OpenAccess)

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Beautiful Proteins in Positively Aware!

I few months back i got a request for  a bunch of renderings of HIV proteins for a non-profit magazine called Positively Aware! Now they’ve been printed :)

PositivelyAwareArticlepngPositivelyAwareArticlepng2PositivelyAwareArticlepng3PositivelyAwareArticlepng4

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Sculpture No 1 & 2 done!

After several weeks of crazy long hours at the shop i finished the first two structures of Ubiquitin and KcsA.

Ubiquitin

Copper, Steel

Ubiquitin is a small regulatory protein  found in almost all tissues of eukaryotic organisms. The cell attaches short chains of Ubiquitin molecules to proteins, which labels them for destruction and subsequent recycling. The Ubiquitin tag directs proteins to the proteasome, which is a large protein complex in the cell that degrades unneeded proteins back into their amino acid constituents. These are then reused to synthesize new proteins.  The constant recycling of proteins not only ensures damaged proteins are removed quickly but also allows rapid regulation of enzyme levels in the cell.

Structurally, Ubiquitin features all of the major structural features of typical proteins including two a-helices a curved b-sheet. Its small size  (76 amino acids) makes it one of the most studied proteins for protein folding and dynamics.

KcsA Potassium Channel

Copper, Steel

Potassium channels form potassium-selective pores that span cell membranes. They are the most widely distributed type of ion channel found in virtually all living organisms. The four identical subunits are situated in a four-fold symmetrical manner around a central pore, which allows potassium ions to pass freely.  At the top of the structure, formed by four loops lining the pore, a selectivity filter is situated which prevents other ions (such as sodium ions) from passing. The correct ions are detected by their size and charge. Note that that no active pumping of ions occurs; it merely allows passive conductance of ions down the con-centration gradient between the two sides of the membrane.

The KcsA is an archetypal membrane protein with eight tightly packed membrane-spanning a-helices.  The four short helices in the center where the chain crosses half the membrane and then returns to the top are a more unusual feature.

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Protein Folding in cuprum

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Doubt on the common assertion that humans are naturally aggressive

Robert Sapol­sky’s study of a baboon tribe which was  transformation from a violent patriarchic, warnongering tribe (like humans) into a peaceful, almost egalitarian and stable society is one of the more fascinating demonstration that the ubiquitous assumtions that humnas are “naturally” violent is unlikely true.

An excellent podcast on the matter is here:

An two articles by Sapolsky:
http://www.sharpbrains.com/blog/2008/04/05/peace-among-primates-by-robert-sapolsky/
http://www.sharpbrains.com/blog/2008/04/12/peace-among-primates-part-2/

Robert M. Sapol­sky, Ph.D., is the John A. and Cyn­thia Fry Gunn Pro­fes­sor of Bio­log­i­cal Sci­ences and a pro­fes­sor of neu­rol­ogy and neu­ro­log­i­cal sci­ences at Stan­ford Uni­ver­sity.

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Alternate States of Proteins Revealed by Detailed Energy Landscape Mapping

After about 2 years of work, millions of CPU hours donated by volunteers from around the globe on Rosetta@HOME and a fruitful collaboration with Daniel Keedy and Jane and David Richardson at Duke University our paper on energy landscapes is finally out! Thank you to everyone who helped and especially to Daniel Keedy @ Duke and all who have donated computing time!

Alternate States of Proteins Revealed by Detailed Energy Landscape Mapping

Michael D. Tyka, Daniel A. Keedy, Ingemar André, Frank DiMaio, Yifan Song, David C. Richardson, Jane S. Richardson and David Baker

contributed equally

What conformations do protein molecules populate in solution? Crystallography provides a high-resolution description of protein structure in the crystal environment, while NMR describes structure in solution but using less data. NMR structures display more variability, but is this because crystal contacts are absent or because of fewer data constraints? Here we report unexpected insight into this issue obtained through analysis of detailed protein energy landscapes generated by large-scale, native-enhanced sampling of conformational space with Rosetta@home for 111 protein domains. In the absence of tightly associating binding partners or ligands, the lowest-energy Rosetta models were nearly all < 2.5 Å CαRMSD from the experimental structure; this result demonstrates that structure prediction accuracy for globular proteins is limited mainly by the ability to sample close to the native structure. While the lowest-energy models are similar to deposited structures, they are not identical; the largest deviations are most often in regions involved in ligand, quaternary, or crystal contacts. For ligand binding proteins, the low energy models may resemble the apo structures, and for oligomeric proteins, the monomeric assembly intermediates. The deviations between the low energy models and crystal structures largely disappear when landscapes are computed in the context of the crystal lattice or multimer. The computed low-energy ensembles, with tight crystal-structure-like packing in the core, but more NMR-structure-like variability in loops, may in some cases resemble the native state ensembles of proteins better than individual crystal or NMR structures, and can suggest experimentally testable hypotheses relating alternative states and structural heterogeneity to function.

imglarge

[Fulltext]

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Alan Turing

Friday I saw an intensely moving and fascinating play on the life and work of Alan Turing (Breaking the Code, written 1986 play by Hugh Whitemore; produced by Strawberry Theatre Workshop; Thu/Fri/Sat 7.30pm @ Erickson Theatre, Seattle). Many years after Turnings work on the Enigma which may well have determined the outcome of the war against Nazi Germany, he was prosecuted by the Governement for his homosexuality and sentenced to chemical sterilization – two year later he commited suicide.

How ironic how often those who fight for freedom against the inhumane oppressors end up being the oppressors and persecutors themselves.

It is sickening how persecution of minority groups continues into so very recent history and to this day. Apparently we have learned nothing. Hey human race, can we please get over this ?

I looked up the official apology issued in 2009 by Prime Minister Gordon Brown on behalf of the UK government:


2009 has been a year of deep reflection – a chance for Britain, as a nation, to commemorate the profound debts we owe to those who came before. A unique combination of anniversaries and events have stirred in us that sense of pride and gratitude which characterise the British experience. Earlier this year I stood with Presidents Sarkozy and Obama to honour the service and the sacrifice of the heroes who stormed the beaches of Normandy 65 years ago. And just last week, we marked the 70 years which have passed since the British government declared its willingness to take up arms against Fascism and declared the outbreak of World War Two. So I am both pleased and proud that, thanks to a coalition of computer scientists, historians and LGBT activists, we have this year a chance to mark and celebrate another contribution to Britain’s fight against the darkness of dictatorship; that of code-breaker Alan Turing.

Turing was a quite brilliant mathematician, most famous for his work on breaking the German Enigma codes. It is no exaggeration to say that, without his outstanding contribution, the history of World War Two could well have been very different. He truly was one of those individuals we can point to whose unique contribution helped to turn the tide of war. The debt of gratitude he is owed makes it all the more horrifying, therefore, that he was treated so inhumanely. In 1952, he was convicted of ‘gross indecency’ – in effect, tried for being gay. His sentence – and he was faced with the miserable choice of this or prison – was chemical castration by a series of injections of female hormones. He took his own life just two years later.

Thousands of people have come together to demand justice for Alan Turing and recognition of the appalling way he was treated. While Turing was dealt with under the law of the time and we can’t put the clock back, his treatment was of course utterly unfair and I am pleased to have the chance to say how deeply sorry I and we all are for what happened to him. Alan and the many thousands of other gay men who were convicted as he was convicted under homophobic laws were treated terribly. Over the years millions more lived in fear of conviction.

I am proud that those days are gone and that in the last 12 years this government has done so much to make life fairer and more equal for our LGBT community. This recognition of Alan’s status as one of Britain’s most famous victims of homophobia is another step towards equality and long overdue.

But even more than that, Alan deserves recognition for his contribution to humankind. For those of us born after 1945, into a Europe which is united, democratic and at peace, it is hard to imagine that our continent was once the theatre of mankind’s darkest hour. It is difficult to believe that in living memory, people could become so consumed by hate – by anti-Semitism, by homophobia, by xenophobia and other murderous prejudices – that the gas chambers and crematoria became a piece of the European landscape as surely as the galleries and universities and concert halls which had marked out the European civilisation for hundreds of years. It is thanks to men and women who were totally committed to fighting fascism, people like Alan Turing, that the horrors of the Holocaust and of total war are part of Europe’s history and not Europe’s present.

So on behalf of the British government, and all those who live freely thanks to Alan’s work I am very proud to say: we’re sorry, you deserved so much better.

Gordon Brown

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100 Most Frequent Internet Search Terms

I’ve been tinkering around, trying to find out what are the most popular searchterms typed into google these days ? Google Trends offers a wealth of data, as do other sites and Meta crawlers and analysis sites. Most published analyses omit adult terms while others (such as Zeitgeist published by Google) concentrate on terms whose search volume is rising quickly compared to their long-term average volume. I feel its insightful to also look at more absolute values though. So here’s a list of the most popular terms I could find: (note this list is approximate and not necessarily complete, nor is the ordering super accurate. The first 10 are fairly accurate though.)

  1. Facebook
  2. Free
  3. How to
  4. YouTube
  5. Online
  6. Lyrics
  7. New
  8. Download
  9. Games
  10. Yahoo
  11. Google
  12. My
  13. School
  14. Porn
  15. Uk
  16. News
  17. Best
  18. Weather
  19. Mail
  20. Sex
  21. Hotmail
  22. Movie
  23. Video
  24. Bank
  25. City
  1. Bank
  2. Ebay
  3. University
  4. Game
  5. Tv
  6. Facebook login
  7. At
  8. 3
  9. Home
  10. MySpace
  11. Time
  12. Map
  13. Car
  14. Music
  15. Movies
  16. College
  17. Jobs
  18. BBC
  19. Club
  20. Up
  21. Park
  22. State
  23. Code
  24. House
  25. Hotel
  1. IT
  2. Canada
  3. Craigslist
  4. Free download
  5. House
  6. Hotel
  7. Black
  8. Yahoo Mail
  9. Girls
  10. Wiki
  11. Love
  12. American
  13. India
  14. Watch
  15. Live
  16. Gmail
  17. White
  18. Book
  19. Office
  20. Football
  21. Videos
  22. Song
  23. Big
  24. CA
  25. Song
  1. Top
  2. London
  3. Hot
  4. Girl
  5. Life
  6. Blue
  7. MSN
  8. Radio
  9. Star
  10. Real
  11. Recipe
  12. You Tube
  13. Texas
  14. Card
  15. Baby
  16. Store
  17. Sports
  18. Health
  19. Australia
  20. Software

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Good Science

This interesting editorial published in Nature (reproduced below without permission) below illustrates a sad truth in the world of science. Since everyone is under huge  political and financial pressure to publish, perform and be the first (the price for second discoveries are already muchly reduced), there is a tendency to over sell and overhype results, publish quickly before the results are properly confirmed and to claim “XYZ is solved” when really it barely worked for one out of 100 cases. Another case is that of Prof Helinga in the field of enzyme design (the results of his groundbreaking enzyme design study were withdrawn, sicne they could not be reproduced, read more about it here ).

I suspect that these cases occur not out of malicious misconduct or out of want for success or ego (i think they partly do though) but largely out of political, social and financial pressure. This does of course not excuse bad science but it raises the question on how to improve the quality of scientific conduct, results and publication. There is a fine line between needing to publish quickly to be the first and scientific rigor. Between boldness and negligence.

Editorial

Nature 461, 1174 (29 October 2009)

Mind the spin

Scientists — and their institutions — should resist the ever-present temptation to hype their results.

The circumstances surrounding the recent announcement of results from an HIV vaccine trial in Thailand are troubling. The sponsors of the US$119-million phase III clinical trial, a consortium led by the US Army, the National Institutes of Health and the Thai government, announced on 24 September that the trial had been a success: an analysis of the data showed that the vaccine had a statistically significant effect on preventing infection.

Other scientists could not immediately assess that claim, however: the full data from the trial were not made available until 20 October, when they were presented at an AIDS vaccine conference in Paris and in an article published online the same day (S. Rerks-Ngarm et al. N. Engl. J. Med. doi:10.1056/nejmoa0908492; 2009). The article contained two other data analyses, not mentioned in the initial announcement, showing smaller effects that were not statistically significant (see page 1187).

The trial’s sponsors defend the premature announcement on the grounds that they had promised to inform the Thai people of the results first; 24 September is also Mahidol Day, the anniversary of the death of the king’s father and a day of national observance in Thailand. The sponsors also argue that announcing the less-upbeat analyses along with the positive result would have been too complicated for the public to understand; they wanted to quickly deliver a clear-cut message on the trial’s findings. Making the full data immediately available to scientists on 24 September would also have been impossible, they add, because of the conference and journal embargoes.

The trial sponsors argue that announcing the less-upbeat analyses along with the positive result would have been too complicated for the public to understand.

To their credit, the scientists involved did emphasize in their public statements that any vaccine effect was “modest”, and that the vaccine itself was of no immediate public-health utility. At the same time, however, they hammered home the message that this was “the first time an HIV vaccine has successfully prevented HIV infection in humans”, and implied that the event was somehow historic. Such statements, together with the selective initial presentation of the data, are well outside the scientific norms for presenting the results of clinical trials. They inevitably create suspicion that the trial sponsors may have put an excessively positive spin on results that are far from clear-cut, in a trial that has long been controversial (T. V. Padma Nature Med. 10, 1267; 2004). The trial has also been six years in the works, and so there seems no particular public-health urgency to justify publication by press conference.

Fortunately, such stories are still rare in science. Witness the way scientists have behaved since the beginning of the current H1N1 flu pandemic, in which the urgent threat to health creates legitimate tensions between getting results out fast and respecting peer review. Most researchers have negotiated this tension well, through a combination of fast-track publication by journals and online pre-publication sharing of preliminary data — but not through hyping their results.

Yet the temptation for scientists and their institutions to spin their research to the media, or to go publicity-mongering, is always there. And — as illustrated by the excessive public-relations campaign surrounding Ida, a fossil presented as a missing link in human evolution (see Nature 459, 484; 2009 and Nature 461, 1040; 2009) — too many in the media will buy into the initial hype.

Such behaviour is corrosive to the process of scholarly scientific communication. Research institutions must not allow it to become the norm.

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