90 research outputs found
Neighborhood design plays a critical role in affecting auto ownership around light rail transit developments
There is a growing interest in exploring the relationship between auto ownership and rail transit investment. However, gaining insight into this relationship is challenging, as researchers must disentangle the impact of rail transit on auto ownership from the influences of the built environment and residential self-selection. In a new research centered on the Minneapolis-St. Paul Metropolitan area, Jason Cao and Xiaoshu Cao examine the effects of light rail transit (LRT), neighborhood design, and self-selection on auto ownership. They find that neighborhood design and residential self-selection influences auto ownership and that LRT does not have an independent impact on auto ownership beyond neighborhood design and self-selection. Their results point to the importance of neighborhood design in rail transit development
Competition and Sustainability Development of a Multi-Airport Region: A Case Study of the Guangdong–Hong Kong–Macao Greater Bay Area
new era in the development of multi-airport regions (MARs) has been in China, especially in the construction of global urban areas such as the Guangdong&ndash
Hong Kong&ndash
Macao Greater Bay Area (GBA). In order to better understand competition and provide significant advice to support sustainable development of Chinese MARs, this paper takes the GBA-MAR as an example, and then explores the competition between airports in this multi-airport region based on route level and its impact on passenger airport choice using three liner models. According to our findings, competition is concentrated on a few air routes in the Northeast&ndash
East Coastal region and the Asia-Pacific region, in which all three airports operate. Although the domestic market of the GBA-MAR has been relatively mature, the international air transport market is still left with considerable room, which is also reflected in connections to the world&rsquo
s cities and tourist destinations. In addition, the research also found that different airport brands created by route type significantly affected passenger airport choice. Overall, the study revealed that whether from a supply or demand aspect, competition between airports in a multi-airport region&mdash
not just airline competition in a single airport&mdash
is an important topic.
Document type: Articl
Effects of solar wind density and velocity variations on the Martian ionosphere and plasma transport - a MHD model study
Solar wind dynamic pressure, consisting solar wind density and velocity , is an important external driver that controls Martian plasma environment. In this study, a 3D magnetohydrodynamic model is applied to investigate the separate influences of solar wind density and velocity on the Martian ionosphere. The spatial distributions of ions in the dayside and near nightside ionosphere under different and are analyzed, as well as the ion transport process. We find that for the same dynamic pressure condition, the ionosphere extends to higher altitudes under higher solar wind density, indicating that a solar wind velocity enhancement event is more efficient at compressing the Martian ionosphere. A higher will result in a stronger induced magnetic field, shielding the Martian ionosphere, preventing the penetration of solar wind particles. For the same dynamic pressure, increasing (decreasing ) leads to a higher horizontal ion velocity, facilitating day-to-night plasma transport. As a result, the ionosphere extends farther into the nightside. Also, the ion outflow flux is larger for high , which may lead to a higher escape rate. Moreover, the strong crustal fields in the southern hemisphere also cause significant effect to the ionosphere, hindering horizontal ion transport. An additional outflow channel is also provided by the crustal field on the southern dayside, causing different responses of flow pattern between local and global scale while the solar wind condition is varied
Advancing Bioaccumulation Modeling and Water Sampling of Ionogenic Organic Chemicals
Although many commercial chemicals can dissociate, the study of the biological and environmental fate of ionogenic organic chemicals (IOCs) is still in its infancy. Uptake of the veterinary drug diclofenac in vultures and cattle was successfully simulated with a newly developed physiologically-based pharmacokinetic model for IOCs, lending credence to diclofenac’s proposed role in South Asian vulture population declines. Proteins and phospholipids rather than total lipids control the tissue distribution of diclofenac.
A method was developed to simultaneously extract neutral and acidic pesticides and benzotriazoles from water samples with recoveries ranging 70-100%. This method was applied to samples from a laboratory calibration experiment of the Polar Organic Chemical Integrative Sampler. The sampler had higher uptake for neutral and acidic pesticides when filled with triphasic sorbent admixture and OASIS MAS sorbent, respectively. While either sorbent can also be applied for methylated benzotriazoles, neither is capable of quantitatively sampling all three compound groups.MAS
Measurement and Spatial Differentiation Characteristics of Transit Equity: A Case Study of Guangzhou, China
Urban public transit is an important solution for narrowing the mobility gap between captive riders and choice riders and to address issues of social equity. An equitable transit system essentially could meet the needs of transit dependents and maximize the scope of public transit services. To acquire a better understanding of transit equity, we use Lorenz curves and the GINI coefficient to measure the relative supply of public transit to the population and employ the spatial overlay method to analyze the matching degree of transit supply and demand in Guangzhou, China. The findings show that there are obvious and unequal differences between the levels of transit service in the internal zones. The spatial coverage rate and number of stop services of the outer city are significantly less than that of the inner and middle city. Eighty percent of the population shares only 36.7% of the public transit supply in Guangzhou. Most communities of low-supply and high-need public transit are distributed contiguously in the eastern Baiyun and southern Huadu districts. This distribution pattern is beneficial to the transit agency, which could improve the supply in these areas to avoid the risk caused when a large number of residents lack access to public transit services. The results could serve as an excellent foundation for planning the handling of spatial gaps in the Guangzhou public transit supply
Comparing importance-performance analysis and three-factor theory in assessing rider satisfaction with transit
Transit ridership depends on its quality of service. Many studies have analyzed rider satisfaction surveys to explore important service attributes and/or identify improvement priorities. Importance-performance analysis (IPA) is capable of serving both purposes. However, it assumes that service attributes have a symmetric influence on rider satisfaction. To relax the assumption, this study applies three-factor theory to classify service attributes into basic, performance, and excitement factors. Using the 2013 data of bus, bus rapid transit (BRT), and metro transit riders from Guangzhou, China, it compares the results from two alternative IPA and two applications of the three-factor theory. Explicit IPA and implicit IPA classify service attributes somewhat differently but produce similar improvement priorities. For the three-factor theory, the importance grid yields more plausible results than regression with dummy variables. This study further concludes divergent improvement priorities for different services: comfort while waiting at station/stop and service reliability for bus; safety while waiting, safety while riding, and comfort while waiting for BRT; and spatial coverage for metro transit. If resources are abundant, transit agencies could also improve customer service for bus and comfort while riding for BRT
Spatio-temporal evolution of port opening in China's 40 years of reform and opening-up period.
In the past 40 years of reform and opening-up, China has developed from an economically closed country to a country that is highly dependent on foreign trade. From the perspective of spatiotemporal evolution, we analyze how port opening promoted China's reform and opening-up process. First, the port development process is divided into four periods. In the start-up period, the pilot open port policy created a platform for foreign cooperation and exchange. During the expansion period, port openings promoted the continuous optimization of the trade structure. In the cooperation period, port openings corresponded with the adjustment of China's overall industrial structure. During the optimization period, port openings provided guarantees for the implementation of a national development strategy. Second, we analyze the distribution of ports and their relationship with cross-border logistics and passenger flow. Based on data of foreign trade and passenger flow, a port openness degree measurement model includes port logistics intensity, passenger flow intensity and port city foreign-trade volume is constructed. There are significant types, geographical differences and grade differences of ports' openness
Impact of high-speed railway construction on spatial relationships in the Guanzhong Plain urban agglomeration
The Guanzhong Plain urban agglomeration is a response to the Belt and Road Initiative in Northwest China that aims to promote regional development. The direct impact of high-speed railway construction is to shorten the spatial-temporal distance among regions, improve the accessibility of regional transportation, and promote socioeconomic linkages. From the perspective of accessibility, this study analyzes the impact of high-speed railway construction on the spatial patterns and county-level economic relationships of the Guanzhong Plain urban agglomeration. The results show that the construction of high-speed railway significantly improves regional accessibility, increases the potential for urban economic development, and gradually narrows the gaps in economic potential among cities. The construction of high-speed railway has increased the intensity of external economic relations among numerous counties in the Guanzhong Plain urban agglomeration, and most of the areas with increased connections are located in the direction of routes extension. The development of the internal economic network of the Guanzhong Plain urban agglomeration is unbalanced, and a complex network is gradually emerging with a few large cities at the core, but the construction of high-speed railway is changing the structure of the economic network. In general, a certain degree of intrinsic coupling exists between regional accessibility change and the evolution of economic relations caused by high-speed railway, reflecting the requirements of the regional overall development strategy
The association between transit access and auto ownership: evidence from Guangzhou, China
In many developing countries, massive investment in transit infrastructure is concurrent with the proliferation of automobiles. Planners expect that investment can slow the growth of auto ownership. However, few studies have examined the relationships between transit access and auto ownership in developing countries, whereas research in developed countries offers mixed findings and the outcomes may not be applicable to developing countries. This study employs a random effect ordered probit model on data collected from Guangzhou residents in 2011–2012. We find that transit access is negatively associated with auto ownership, after controlling for demographics and other built environment variables. This result suggests that, although income is the dominant driver for auto ownership in growing developing countries, transit investment is a promising strategy to slow the growth of auto ownership. This study also highlights the importance of addressing spatial dependency in clustered data
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