New Methods of Census Record Linking

The Minnesota Population Center (MPC) has released linked datasets through its NAPP and IPUMS projects, making them readily accessible to researchers. Prior to the availability of complete count census microdata from the MPC, researchers applied various forms of record-linking software. This essay describes the techniques used in the MPC's linking program and briefly compares this technique with those used by other researchers. The key feature of the MPC linking method is the construction of cumulative name similarity scores, based on approximately 2.5 billion record comparisons; we also use support vector mechanics to classify potential links. This article explains modifications made for the final linked datasets and includes a discussion of the role of weighting variables when using linked data.     

Can salmonids (Oncorhynchus spp.) be identified to species using vertebral morphometrics?

Remains of anadromous Pacific salmon and trout (genus Oncorhynchus) are common in archaeological sites from California to Alaska; however, morphological similarity generally precludes species identification, limiting the range of questions that salmonid remains can address in relation to past human use and ongoing efforts in conservation biology. We developed a relatively simple, rapid, and non-destructive way to classify salmon and trout vertebrae from archaeological contexts to species using length, height and the ratio of length to height. Modern reference material was obtained from all seven anadromous Oncorhynchus species native to the west coast of North America. A minimum of ten adult Chinook (Oncorhynchus tshawytscha), chum (Oncorhynchus keta), coho (Oncorhynchus kisutch), pink (Oncorhynchus gorbuscha), and sockeye salmon (Oncorhynchus nerka) and cutthroat (Oncorhynchus clarki clarki) and steelhead trout (Oncorhynchus mykiss) were skeletonized and vertebra length and height were measured. Morphometric analyses compared species classification success based on Linear Discriminant Analysis (LDA), Classification and Regression Trees (CART), and randomForest, with CART performing the best. Classification analyses used all seven species individually, but because of considerable overlap among several species we also conducted analyses on four species groupings. We assigned Chinook salmon and cutthroat to their own groups based on their dissimilarities from each other and the other species. The remaining species were divided into two group complexes (a) chum, coho, and steelhead; and (b) pink and sockeye. When we grouped species according to similar morphology, CART overall success rates increased, ranging from 92 to 100%. Individual species with the highest successful classification rates using CART were Chinook salmon and cutthroat, from 92 to 100%, respectively. We applied our classification to an assemblage of ancient (1000–3000 year old) salmonid vertebrae from the Swiftwater Rockshelters excavations on the upper Wenatchee River in Washington State, U.S.A.     

The rise and ruin of a medieval port town: A reconsideration of the development of Julfar

Julfar was a major port town of the Persian Gulf during the fourteenth and fifteenth centuries AD. A possession of the Hormuzi empire, it was a lucrative source of taxes and pearls, and a port of trade for northern Oman, tapping into maritime trading networks connecting the Middle East with Africa, India, Southeast Asia and China. The site is found north of modern Ras Al-Khaimah, UAE. Julfar Al-Nudud was previously considered to be a late suburb of an urban core, Julfar Al-Mataf, and is located on a creek opposite the latter. However, excavations in 2010 indicated that Al-Nudud was part of the original urban core, which had grown up on either side of the creek. Moreover, re-examination of previous work in Al-Mataf, where a large mosque and fortification were excavated (by British and French teams), shows that the two areas followed different trajectories. Significant occupation in Al-Nudud and southern Al-Mataf (revealed by previous Japanese excavations) ended before the start of the sixteenth century, while use of the mosque and fort in central Al-Mataf continued into the seventeenth century, albeit discontinuously. A revised concordance of the phases derived from the work of various archaeological teams is therefore proposed.