Managing the evolution of dataflows with VisTrails

Journal ArticleScientists are now faced with an incredible volume of data to analyze. To successfully analyze and validate various hypotheses, it is necessary to pose several queries, correlate disparate data, and create insightful visualizations of both the simulated processes and observed phenomena. Data exploration through visualization requires scientists to go through several steps. In essence, they need to assemble complex workflows that consist of dataset selection, specification of series of operations that need to be applied to the data, and the creation of appropriate visual representations, before they can finally view and analyze the results. Often, insight comes from comparing the results of multiple visualizations that are created during the data exploration process. For example, by applying a given visualization process to multiple datasets; by varying the values of simulation parameters; or by applying different variations of a given process (e.g., which use different visualization algorithms) to a given dataset. Unfortunately, today this exploratory process is far from interactive and contains many error-prone and time-consuming tasks

Provenance for visualizations: reproducibility and beyond

Journal ArticleThe demand for the construction of complex visualizations is growing in many disciplines of science, as users are faced with ever increasing volumes of data to analyze. The authors present VisTrails, an open source provenance-management system that provides infrastructure for data exploration and visualization

Compound-Specific Isotopic Analysis of Meteoritic Amino Acids as a Tool for Evaluating Potential Formation Pathways

Measurements of stable hydrogen, carbon, and nitrogen isotopic ratios (delta D, delta C-13, delta N-15) of organic compounds can reveal information about their origin and formation pathways. Several formation mechanisms and environments have been postulated for the amino acids detected in carbonaceous chondrites. As each proposed mechanism utilizes different precursor molecules, the isotopic signatures of the resulting amino acids may point towards the most likely of these proposed pathways. The technique of gas chromatography coupled with mass spectrometry and isotope ratio mass spectrometry provides compound-specific structural and isotopic information from a single splitless injection, enhancing the amount of information gained from small amounts of precious samples such as carbonaceous chondrites. We have applied this technique to measure the compound-specific C, N, and H isotopic ratios of amino acids from seven CM and CR carbonaceous chondrites. We are using these measurements to evaluate predictions of expected isotopic enrichments from potential formation pathways and environments, leading to a better understanding of the origin of these compounds