{"accessLevel": "public", "bureauCode": ["010:12"], "contactPoint": {"@type": "vcard:Contact", "fn": "U.S. Geological Survey Alaska Science Center", "hasEmail": "mailto:ascweb@usgs.gov"}, "description": "An implementation of Quantitative Fatty Acid Signature Analysis (QFASA) in R.  QFASA is a method of estimating the diet composition of predators.  The fundamental unit of information in QFASA is a fatty acid signature (signature), which is a vector of proportions describing the fatty acid composition of adipose tissue.  Signature data from at least one predator and from samples of all potential prey types are required.  Calibration coefficients, which adjust for the differential metabolism of individual fatty acids by predators, are also required.  Given those data inputs, a predator signature is modeled as a mixture of potential prey signatures and its diet estimate is obtained as the mixture that minimizes a measure of distance between the observed and modeled signatures.  A variety of estimation options, goodness-of-fit diagnostic procedures to assess the suitability of estimates, and simulation capabilities are implemented.  Please refer to the package vignette and the documentation files for individual functions for details and references.", "distribution": [{"@type": "dcat:Distribution", "accessURL": "http://dx.doi.org/10.5066/F71G0JC9", "description": "Landing page for access to the data", "format": "XML", "mediaType": "application/http", "title": "Digital Data"}, {"@type": "dcat:Distribution", "description": "The metadata original format", "downloadURL": "https://data.usgs.gov/datacatalog/metadata/USGS.ASC64.xml", "format": "XML", "mediaType": "text/xml", "title": "Original Metadata"}], "identifier": "http://datainventory.doi.gov/id/dataset/USGS_ASC64", "keyword": ["biota", "diet estimation", "distance measure", "chi-square distance measure", "clustering", "R", "Aitchison distance measure", "quantitative fatty acid signature analysis", "numerical optimization", "diet composition", "linear mixing model", "Rsolnp", "USGS:ASC64", "simulation", "QFASA", "bootstrap sampling", "predator-prey", "Kullback-Leibler distance measure", "goodness-of-fit"], "modified": "2020-11-25T00:00:00Z", "publisher": {"@type": "org:Organization", "name": "U.S. Geological Survey"}, "theme": ["geospatial"], "title": "qfasar: Quantitative Fatty Acid Signature Analysis in R"}