Non-destructive search for interstellar dust using synchrotron microprobes

Westphal, A. J.; Allbrink, A.; Allen, Carlton C.; Bajt, Saša; Bastien, Ron K.; Bechtel, Hans A.; Bleuet, Pierre; Borg, J.; Bowker, S.; Brenker, Frank E.; Bridges, J. C.; Brownlee, D. E.; Burchell, M. J.; Burghammer, Manfred; Butterworth, A. L.; Campanile, Antonella; Cloetens, Peter; Cody, George D.; Ferroir, T.; Ferrari, Kevin; Floss, C.; Flynn, G. J.; Frank, D.; Gainsforth, Z.; Grün, E.; Harmer, M.; Hoppe, P.; Kearsley, A. T.; Kulkarni, S.; Lai, Barry; Lemelle, Laurence; Leroux, Hugues; Lettieri, R.; Marchant, W.; McCreadie, B.; Nittler, L. R.; Ogliore, R. C.; Postberg, F.; Rigamonti, Carlo; Sandford, S. A.; Schmitz, Sylvia; Silversmit, Geert; Simionovici, A.; Sperry, Gerry; Srama, R.; Stadermann, F. J.; Stephan, T.; Stroud, Rhonda M.; Susini, J.; Sutton, S. R.; Thompson, V.; Toucoulou, R.; Trieloff, M.; Tsou, P.; Tsuchiyama, A.; Tyliczszak, T.; Vekemans, Bart; Vincze, László; Warren, John E.; Yahnke, Tom; Zevin, D.; Zolensky, M. E.

doi:10.1063/1.3399239

Cited by 9 publications

(14 citation statements)

References 6 publications

(6 reference statements)

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“…Isotopic analyses, to be carried out after the ISPE, will be required to definitively test whether particles are interstellar or not; therefore, here, we only report tentative results. Track I1027, 1,9, originally tentatively identified as an interstellar candidate, was mapped in detail and presented elsewhere (see Westphal et al 2010). However, it was later removed from the ISDC list due to its high Ca/Fe and Zn/Fe ratios.…”

Section: Isdc Resultsmentioning

confidence: 99%

“…After extraction, IS candidates were imaged directly in picokeystones, prepared from the original Stardust low-density (0.02-0.04 g cm À3 ) silica aerogel capture medium. The picokeystones were confined within containers consisting of two 70 nm Si3N4 membranes (Westphal et al 2010).…”

Section: Samples and Synchrotron Experimental Setupmentioning

confidence: 99%

“…Analyzed features were identified by volunteers of the Stardust@home initiative (Westphal et al 2005(Westphal et al , 2010(Westphal et al , 2014a(Westphal et al , 2014b and extracted at NASA's Johnson Space Center in Houston, Texas (Frank et al 2013). After extraction, IS candidates were imaged directly in picokeystones, prepared from the original Stardust low-density (0.02-0.04 g cm À3 ) silica aerogel capture medium.…”

Section: Samples and Synchrotron Experimental Setupmentioning

confidence: 99%

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Stardust Interstellar Preliminary Examination VI: Quantitative elemental analysis by synchrotron X‐ray fluorescence nanoimaging of eight impact features in aerogel

Simionovici

Lemelle

Cloetens

et al. 2014

Meteorit & Planetary Scien

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Abstract-Hard X-ray, quantitative, fluorescence elemental imaging was performed on the ID22NI nanoprobe and ID22 microprobe beam lines of the European Synchrotron Research facility (ESRF) in Grenoble, France, on eight interstellar candidate impact features in the framework of the NASA Stardust Interstellar Preliminary Examination (ISPE). Three features were unambiguous tracks, and the other five were identified as possible, but not definite, impact features. Overall, we produced an absolute quantification of elemental abundances in the 15 ≤ Z ≤ 30 range by means of corrections of the beam parameters, reference materials, and fundamental atomic parameters. Seven features were ruled out as interstellar dust candidates (ISDC) based on compositional arguments. One of the three tracks, I1043,1,30,0,0, contained, at the time of our analysis, two physically separated, micrometer-sized terminal particles, the most promising ISDCs, Orion and Sirius. We found that the Sirius particle was a fairly homogenous Ni-bearing particle and contained about 33 fg of distributed high-Z elements (Z > 12). Orion was a highly heterogeneous Fe-bearing particle and contained about 59 fg of heavy elements located in hundred nanometer phases, forming an irregular mantle that surrounded a low-Z core. X-ray diffraction (XRD) measurements revealed Sirius to be amorphous, whereas Orion contained partially crystalline material (Gainsforth et al. 2014). Within the mantle, one grain was relatively Fe-Ni-Mn-rich; other zones were relatively Mn-Cr-Ti-rich and may correspond to different spinel populations. For absolute quantification purposes, Orion was assigned to a mineralogical assemblage of forsterite, spinel, and an unknown Fe-bearing phase, while Sirius was most likely composed of an amorphous Mg-bearing material with minor Ni and Fe. Owing to its nearly chondritic abundances of the nonvolatile elements Ca, Ti, Co, and Ni with respect to Fe, in combination with the presence of olivine and spinel as inferred from XRD measurements, Orion had a high probability of being extraterrestrial in origin.

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Section: Isdc Resultsmentioning

confidence: 99%

Section: Samples and Synchrotron Experimental Setupmentioning

confidence: 99%

Section: Samples and Synchrotron Experimental Setupmentioning

confidence: 99%

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Stardust Interstellar Preliminary Examination VI: Quantitative elemental analysis by synchrotron X‐ray fluorescence nanoimaging of eight impact features in aerogel

Simionovici

Lemelle

Cloetens

et al. 2014

Meteorit & Planetary Scien

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“…Most such efforts involve visual tasks such as tagging images or locating image features (1)(2)(3). In contrast, Foldit is a multiplayer online scientific discovery game, in which players become highly skilled at creating accurate protein structure models through extended game play (4,5).…”

mentioning

confidence: 99%

Algorithm discovery by protein folding game players

Khatib¹,

Cooper²,

Tyka³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

478

374

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Foldit 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.citizen science | crowd-sourcing | optimization | structure prediction | strategy C itizen science is an approach to leveraging natural human abilities for scientific purposes. Most such efforts involve visual tasks such as tagging images or locating image features (1-3). In contrast, Foldit is a multiplayer online scientific discovery game, in which players become highly skilled at creating accurate protein structure models through extended game play (4, 5). Foldit recruits online gamers to optimize the computed Rosetta energy using human spatial problem-solving skills. Players manipulate protein structures with a palette of interactive tools and manipulations. Through their interactive exploration Foldit players also utilize user-friendly versions of algorithms from the Rosetta structure prediction methodology (6) such as wiggle (gradient-based energy minimization) and shake (combinatorial side chain rotamer packing). The potential of gamers to solve more complex scientific problems was recently highlighted by the solution of a long-standing protein structure determination problem by Foldit players (7).One of the key strengths of game-based human problem exploration is the human ability to search over the space of possible strategies and adapt those strategies to the type of problem and stage of problem solving (5). The variability of tactics and strategies s...

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“…Games such as the ESP game [23] and Peekaboom [24] use human image-recognition ability to produce labeled images from gameplay. Image recognition has also been used for finding particular features of interest in scientific data, such as looking for signs of interstellar dust [25], measuring and aligning features on a planet's surface [15], and classifying galaxy shapes [11]. Most such work is heavily image-based, and these projects have been successful in motivating players to sift through large image sets, which would otherwise be a mundane task.…”

Section: Related Workmentioning

confidence: 99%

The challenge of designing scientific discovery games

Cooper

Treuille

Barbero

et al. 2010

Proceedings of the Fifth International Conference on the Foundations of Digital Games

135

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Incorporating the individual and collective problem solving skills of non-experts into the scientific discovery process could potentially accelerate the advancement of science. This paper discusses the design process used for Foldit, a multiplayer online biochemistry game that presents players with computationally difficult protein folding problems in the form of puzzles, allowing ordinary players to gain expertise and help solve these problems. The principle challenge of designing such scientific discovery games is harnessing the enormous collective problem-solving potential of the game playing population, who have not been previously introduced to the specific problem, or, often, the entire scientific discipline. To address this challenge, we took an iterative approach to designing the game, incorporating feedback from players and biochemical experts alike. Feedback was gathered both before and after releasing the game, to create the rules, interactions, and visualizations in Foldit that maximize contributions from game players. We present several examples of how this approach guided the game's design, and allowed us to improve both the quality of the gameplay and the application of player problem-solving.

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Non-destructive search for interstellar dust using synchrotron microprobes

Cited by 9 publications

References 6 publications

Stardust Interstellar Preliminary Examination VI: Quantitative elemental analysis by synchrotron X‐ray fluorescence nanoimaging of eight impact features in aerogel

Stardust Interstellar Preliminary Examination VI: Quantitative elemental analysis by synchrotron X‐ray fluorescence nanoimaging of eight impact features in aerogel

Algorithm discovery by protein folding game players

The challenge of designing scientific discovery games

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