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.
Antitumor activities of (2"R)-4'-O-tetrahydropyranyl-adriamycin (THP) and its combination with other antitumor agents on murine tumors.
(2''R)-4'-O-Tetrahydropyranyladriamycin (THP) is a new derivative of doxorubicin (adriamycin, ADM). The concentrations of THP and ADM required to inhibit by 50% the growth of a cultured L1210 cells was 0.003 microgram/ml and 0.016 microgram/ml, respectively. Various therapeutic designs of combinations of THP with other antitumor agents were investigated in vivo using the L1210 murine leukemia. The combination of THP with cytosine arabinoside (Ara-C), cyclocytidine hydrochloride (Cyclo-C), 6-mercaptopurine (6-MP) and cyclophosphamide (EX) showed a great effectiveness following daily intraperitoneal treatment from days 1 to 10. High therapeutic effects were also obtained with the combinations of THP with Ara-C, Cyclo-C, vincristine (VCR) and EX following intravenous combination therapy one day following implantation of L1210 leukemia. Schedule dependency and its therapeutic efficacy of THP were examined. THP showed almost the same antitumor activity on the solid-type sarcoma-180 or solid-type Ehrlich carcinoma as ADM by intraperitoneal or intravenous treatment. THP showed some superior activity to ADM in the advanced stage of L1210 leukemia. High antitumor activity of THP on murine leukemia L1210 has been reported by Tsuruo et al. (Cancer Res. 42: 1462-1467, 1982) and was also confirmed. THP gave many mice cures, especially in the intravenous treatment.