Creating a replicable, valid cross-platform buffering technique: the sausage network buffer for measuring food and

Ann Forsyth1, David Van Riper, Nicole Larson

  • 1Department of City and Regional Planning, Cornell University, Ithaca, NY, USA. forsyth@cornell.edu

Summary

A new "sausage" buffer method for geographic information systems (GIS) offers reproducible measurements of neighborhood food and physical activity environments, aiding obesity research.

Related Concept Videos

Buffer Systems in the Body01:19

Buffer Systems in the Body

Chemical buffers play a critical role in the body's regulation of pH levels. These systems contain one or more compounds that stabilize pH changes by neutralizing strong acids or bases. When pH levels drop, hydrogen ions bind to a weak base; when pH levels rise, hydrogen ions are released. This dynamic process helps maintain pH within a narrow and stable range essential for normal physiological function.
A typical buffer system in bodily fluids includes a weak acid and its corresponding anion,...
Buffer Effectiveness02:19

Buffer Effectiveness

Buffer solutions do not have an unlimited capacity to keep the pH relatively constant . Instead, the ability of a buffer solution to resist changes in pH relies on the presence of appreciable amounts of its conjugate weak acid-base pair. When enough strong acid or base is added to substantially lower the concentration of either member of the buffer pair, the buffering action within the solution is compromised.
The buffer capacity is the amount of acid or base that can be added to a given volume...
Buffers: Buffer Capacity01:09

Buffers: Buffer Capacity

Buffer capacity is the quantitative measure of a buffer to resist the change in pH. As shown in the following equation, the buffer capacity, denoted by 'beta', is expressed as the number of moles of acid or base needed to change the pH of a one-liter buffer solution by 1 unit. Here, Ca and Cb indicate the number of moles of acid and base, respectively. Note that dpH represents the change in pH.
In the graph, pH is plotted as a function of the number of moles of base (Cb) added to a weak acid...