The 1 km buffer measure performs as well as the Census tract measure but requires knowledge of individuals' addresses and is much more computationally intensive.
Businesses within each category were aggregated for four geographic units: (1) Census block group, (2) Census tract, (3) ZIP code and (4) a 1 km buffer measure around each individual's home.
Three of these four were area measures: Census block group, Census tract and ZIP code; and the fourth was a buffer measure, which was a 1 km buffer around an individual's residence.
The measurement of the concentration distribution of a macromolecule across a solution column by absorption optics usually requires optical transmission profiles of both the sample solution and the buffer, measured under identical conditions, to calculate the absorbance as the logarithm of the ratio of reference to sample intensity.
For this purpose, appropriate dilutions of these antibodies in PERM/WASH were incubated with the cells for 30 min, next cells were washed twice with PERM/WASH and one more time in FACS buffer and after resuspension in FACS buffer measured with a FACS Calibur (BD Biosciences).
These covariates included proximity measures (distance to nearest major road, intersection, truck route, railway, railyard, coastline, airport, and port) and buffer measures (major road length, truck route length, land-use category, long-term vegetation index, population density, and emission sources).
Although Canada has greater total land size and natural space area, the average natural space within the 5 km buffer measured in this study was lower than those measured in the Netherlands and England [ 27, 28].
(b) Degradation of ADP (10 μmol/l) by apyrase (0.32 u/ml) present in the platelet saline buffer measured after 2 min in nominally Ca2+-free saline or following addition of 2 mmol/l Mg2+.
The results were calculated as a percentage of the GLP-1 content (secreted plus intracellular) per well and were normalised to the basal secretion in saline buffer measured in parallel on the same day.
When examining associations between local destinations and walking it is common to count local destinations using street network buffers measured at various distances to mitigate spatial data aggregation issues caused by scale and the Modifiable Areal Unit Problem.
Some previous studies have analyzed retrieved PUC buffers, measuring a minimum volumetric wear rate (1.4 14 mm/year), and a low number of wear debris particles without tissular reaction [ 66, 67], supporting previous in vivo studies [ 46].
