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Full-Text Articles in Human Geography
A Microwave Digestion Method For The Extraction Of Phytoliths From Herbarium Specimens, Jeffrey Parr, V Dolic, Graham Lancaster, William Boyd
A Microwave Digestion Method For The Extraction Of Phytoliths From Herbarium Specimens, Jeffrey Parr, V Dolic, Graham Lancaster, William Boyd
Jeffrey Parr
The extraction of phytoliths from herbarium and/or fresh plant material to obtain a suite of comparative reference samples is an essential component of palaeobotanical studies for the accurate interpretation of fossil phytolith assemblages. A number of established methods have been employed to extract phytoliths from plant material including dry ashing and acid digestion. However, while these methods produce good results, they can be time consuming and have the potential to produce results with some cross-contamination if not monitored closely. In this study, we trial an alternative method using microwave digestion, and compare the results to those produced using a conventional …
Computing Travel Time When The Exact Address Is Unknown: A Comparison Of Point And Polygon Zip Code Approximation Methods, Ethan M. Berke, Xun Shi
Computing Travel Time When The Exact Address Is Unknown: A Comparison Of Point And Polygon Zip Code Approximation Methods, Ethan M. Berke, Xun Shi
Dartmouth Scholarship
Travel time is an important metric of geographic access to health care. We compared strategies of estimating travel times when only subject ZIP code data were available.Using simulated data from New Hampshire and Arizona, we estimated travel times to nearest cancer centers by using: 1) geometric centroid of ZIP code polygons as origins, 2) population centroids as origin, 3) service area rings around each cancer center, assigning subjects to rings by assuming they are evenly distributed within their ZIP code, 4) service area rings around each center, assuming the subjects follow the population distribution within the ZIP code. We used …