Observations on regression analysis of travel distance on airline distance
In the modeling of urban areas airline distance is often used as a proxy for travel time or distance. This practice has been justified by a high coefficient of determination (R2) between these variables in a random sample of pairs of traffic zones. The ratio of travel distance to airline distance has been used as a measure of network efficiency and called the route factor. This exercise uses hypothetical examples to examine network structure, congestion, and trip production as determinants of route factors and of R2 values of travel distance regressed on airline distance.
The Lowry Model Heritage
Abstract The Lowry model constituted a breakthrough of a particularly intractable conceptual barrier. Notwithstanding its attractive features, including the promise of meaningful operationality, the model has been implemented in only a few domestic applications; its adapters abroad have had more success. In this process, the model has gradually been transformed to more satisfactorily meet the requirements of the regional and transportation planning agencies that depend on allocation modeling. As newly developing conceptual embellishments are made operational, the Lowry model should become an instrument that will enlarge our knowledge of the metropolis and lay a solid foundation for the next generation of models.
Multiple-dose pharmacokinetics of moxisylyte after oral administration to healthy volunteers.
The pharmacokinetics of moxisylyte in plasma and urine was investigated after oral administration. Twelve subjects were treated orally, twice daily with 240 mg of the drug for 6 days; on day 7, the subjects received a last dose of 240 mg of moxisylyte. Moxisylyte was assayed in plasma and urine by a specific HPLC method with fluorimetric detection. Moxisylyte was absorbed rapidly and changed to its metabolites immediately after drug administration; unchanged moxisylyte was not found in plasma. Two metabolites were found in plasma and urine: conjugated desacetylmoxisylyte (DAM) and the conjugate of desmethylated DAM (MDAM). The pharmacokinetic parameters determined after the first oral administration were not modified on multiple dosing. The apparent elimination half-lives of conjugated DAM and MDAM were 2.3 and 3.5 h, respectively. Elimination of these two metabolites in urine averaged 50 and 10%, respectively.