The shift of travel demand policies from the conventional supply oriented policies to management oriented policies has made the effectiveness of conventional models questionable. However, although the new generation travel demand models have theoretically appealing backgrounds, they have so far failed to fully attract the practitioners to apply them for practical purposes. Lack at proper understanding and wrong perceptions of the new generation models have contributed to the gap between research and practice. This paper suggests a way to incorporate the features of new generation models using ordinary PT (person trip) data, to get an optimum model. Based on this, we propose a model that captures the link among travel decisions of a day as a travel pattern. We also illustrate the practical advantages of the new generation models, comparing with conventional models, in evaluating policies by an empirical study.
In most developed countries, the population of the elderly and disabled is growing rapidly. These individuals require transportation service suited to their needs. Such service may be provided by applying emerging technologies to dial-a-ride transit. This research develops a methodology to quantitatively evaluate the impact of paratransit services on a traveler’s mode choice behavior. The mode choice model explicitly considers availability of alternative modes and includes latent factors to account for taste heterogeneity. Stated preferences are also used to elicit preferences for new paratransit services. The methodology is empirically tested with data collected in Winston-Salem, North Carolina. The model system developed is applied to evaluate the effect of improving service attributes and the impact of the introduction of new cost-effective modes on modal shares. Results of the policy analysis indicate that ( a) transit policy changes, such as fare reduction, would have little effect on automobile driver and automobile passenger shares; ( b) an improved reservation system for dial-a-ride services would produce shifts in mode share; ( c) the proposed new bus deviation service was favored; ( d) free bus service reduces dial-a-ride share; and ( e) an increase in awareness of a dial-a-ride system would significantly increase its share.
Virulence factors, such as staphylococcal enterotoxin A (SEA), are contained within membrane vesicles (MVs) in the cell membrane of Staphylococcus aureus. In this study, the effects of the growth stage on quantitative and qualitative changes in the components contained in the MVs of S. aureus SEA-producing strains were examined. Changes in the expression levels of S. aureus genes were examined at each growth stage; phenol-soluble modulin (PSM) gene reached a maximum after 8 h, and the expression of cell membrane-related genes was decreased after 6 h. Based on these gene expression patterns, MVs were prepared at 6, 17, and 24 h. The particle size of MVs did not change depending on the growth stage. MVs prepared after culture for 17 h maintained their particle size when stored at 23 °C. The amount of SEA in the culture supernatant and MVs were not correlated. Bifunctional autolysin, a protein involved in cell wall biosynthesis/degradation, was increased in MVs at 17 h. The expression pattern of inflammation-related genes in human adult low calcium high temperature (HaCaT) cells induced by MVs was different for each growth stage. The inclusion components of S. aureus-derived MVs are selective, depend on the stage of growth, and may play an important role in toxicity.
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