Search

Increased negative intrathoracic pressure that occurs during pharyngeal obstruction can increase thoracic fluid volume that may contribute to lower airway narrowing in individuals with obstructive sleep apnea (OSA) and asthma. Our previous study showed that fluid accumulation in the thorax induced by simulated OSA can increase total respiratory resistance. However, the effect of fluid shift on lower airway narrowing has not been investigated. To examine the effect of fluid accumulation in the thorax on the resistance of the lower airway. Non-asthma participants and individuals with (un)controlled asthma were recruited and underwent a single-day experiment. A catheter with six pressure sensors was inserted through the nose to continuously measure pressure at different sites of the airway, while a pneumotachograph was attached to a mouthpiece to record airflow. To simulate obstructive apneas, participants performed 25 Mueller maneuvers (MMs) while lying supine. Using the recordings of pressure sensor and airflow, total respiratory (RT), lower respiratory components (RL), and upper airway (RUA) resistances were calculated before and after MMs. Generalized estimation equation method was used to find the predictors of RL among variables including age, sex, body mass index, and the effect of MMs and asthma. Eighteen participants were included. Performing MMs significantly increased RT (2.23 ± 2.08 cmH2O/L/s, p = 0.003) and RL (1.52 ± 2.00 cmH2O/L/s, p = 0.023) in participants with asthma, while only RL was increased in non-asthma group (1.96 ± 1.73 cmH2O/L/s, p = 0.039). We found the model with age, and the effect of MMs and asthma severity generated the highest correlation (R2 = 0.69, p < 0.001). We provide evidence that fluid accumulation in the thorax caused by excessive intrathoracic pressure increases RL in both non-asthma and asthma groups. The changes in RL were related to age, having asthma and the effect of simulated OSA. This can explain the interrelationship between OSA and asthma. [ABSTRACT FROM AUTHOR]

Purpose: Nocturnal asthma is a sign of asthma worsening and could be partially due to more fluid drawn into the thorax during sleep by gravitational force and/or pharyngeal collapse in those with obstructive sleep apnea. Wearing compression stockings during the day reduces fluid shift from the legs to the neck overnight. However, the potential effect of wearing compression stockings to reduce fluid accumulation in the leg and to improve nocturnal small airway narrowing in patients with asthma has not been investigated. This study investigates whether reducing leg fluid volume by wearing compression stockings during the day would attenuate small airway narrowing in patients with asthma before and after sleep. Methods: We enrolled 11 participants with asthma. All participants underwent overnight polysomnography with or without wearing compression stockings for 2 weeks. Before and after sleep, leg fluid volume (LFV) was measured by bioelectrical impedance, and airway narrowing was primarily assessed by respiratory system resistance and reactance at 5 Hz (R5 and X5 respectively) using oscillometry. Results: After 2 weeks of wearing compression stockings, the LFV measured in the evening was reduced (∆ = − 192.6 ± 248.3 ml, p = 0.02), and R5 and X5 improved (∆ = − 0.7 ± 0.9 cmH2O/L/s, p = 0.03 and 0.2 ± 1.4 cmH2O/L/s, p = 0.05 respectively). No changes were observed in the morning. Conclusions: Preventing fluid retention in the legs by wearing compression stockings for 2 weeks during the day, reduced LFV and airway narrowing in the evening in all participants with asthma, but not in the morning after sleep. [ABSTRACT FROM AUTHOR]

Since the Bonn 2011 conference, the "water-energy-food" (WEF) nexus has aroused global concern to promote sustainable development. The WEF nexus is a complex, dynamic, and open system containing interrelated and interdependent elements. However, the nexus studies have mainly focused on natural elements based on massive earth observation data. Human elements (e.g., society, economy, politics, culture) are described insufficiently, because traditional earth observation technologies cannot effectively perceive socioeconomic characteristics, especially human feelings, emotions, and experiences. Thus, it is difficult to simulate the complex WEF nexus. With the development of earth observation sensor technologies and human activity perception methods, geographical big data covering both human activities and natural elements offers a new opportunity for in-depth WEF nexus analysis. This study proposes a five-step framework by leveraging geographical big data mining to dig for the hidden value in the data of various natural and human elements. This framework can enable a thorough and comprehensive analysis of the WEF nexus. Some application examples of the framework, major challenges, and possible solutions are discussed. Geographical big data mining is a promising approach to enhance the analysis of the WEF nexus, strengthen the coordinated management of resources and sectors, and facilitate the progress toward sustainable development. [ABSTRACT FROM AUTHOR]

The joint landscape ecological risk as well as ecological corridors for ecological restoration area identification is of great significance to the past evolution and future development of landscapes. Ecological risks were assessed based on the landscape pattern and functional changes in Pengyang County in 2000, 2010, and 2020; ecological restoration areas were divided based on ecological risks and security pattern. Results showed that the ecological risk types in Pengyang County were mainly low risk from 2000 to 2010 and distributed in the central region, while the high-risk areas increased from 2010 to 2020 and were concentrated in the southern residential area. According to a comprehensive assessment of the landscape ecological risks, an ecological security pattern consisting of 17 ecological source points and 34 potential ecological corridors with an average length of 6.57 km was identified. Three ecological restoration areas were eventually identified: mining restoration areas, mountain restoration area, and urban restoration area. Our results would provide an important perspective for the sustainable development of regional natural landscape resources. [ABSTRACT FROM AUTHOR]

Characterizing the availability of opportunities to residents has been a long-term aim in health care geographic investigation. It is important to measure the degree of inequity in health care accessibility and to identify underserved areas, due to the uneven distribution of health care services. In this study, JavaScript was used to calculate travel time based on Amap, as this can provide a more reliable data support to measure the health care accessibility in Xi'an communities, China. Based on the overall equity, herein, an attempt was made to quantify the equity of health care accessibility, and to identify health care underserved areas inside the different communities. Results show that the accessibility to low-level health care services is high in the northern areas and low in the southern areas, while the accessibility to high-level and comprehensive health care services shows a clear core-periphery spatial structure. Moreover, the overall equity of the health care accessibility is relatively low, and the inequity of high-level health care accessibility is further aggravated. Furthermore, the quantified equity of accessibility to high-level and comprehensive health care services in the central urban areas is better; however low-level health care services are relatively inadequate. There are significant differences among health care underserved areas, in particular, for the worst equity and the lowest accessibility areas (A1) and the worse equity and the lowest accessibility areas (B1) in high-level underserved areas. Notably, the sharing of health care services and the reasonable flow of health technical personnel among different levels of health institutions can make the high-level health care services in the central urban areas have a greater trickle effect on the surrounding areas. [ABSTRACT FROM AUTHOR]

Based on geographic information system (GIS) spatial analysis technology, the spatial pattern of raster grid transport accessibility for the Guangdong-Hong Kong-Macao Greater Bay area was studied and the states of spatial connectedness were simulated using highway passenger transport, railway passenger transport, port passenger transport and aviation passenger transport data. The result shows that transport accessibility within the Guangdong-Hong Kong-Macao Greater Bay area costs 'one hour' and the spatial distribution of accessibility in the area presents clear 'core-periphery' spatial characteristics, with Guangzhou, Foshan, Shenzhen constituting the core. The transport accessibility of Guangdong-Hong Kong-Macao is high. Average accessibility of urban nodes as measured by travel time is 0.99 h, and the areas accessible within 1.42 h occupy 79.14% of the total area. Most of the areas with the lowest accessibility are found in the peripheral area, with the worst accessibility being 4.73 h. Compared with the west-side cities, the economically developed east-side cities of the Guangdong-Hong Kong-Macao Greater Bay area have higher connectivity with roads, railways, ports, and aviation transport. Guangzhou, Foshan, Zhuhai, Shenzhen, Hong Kong and Macao are closely linked. The higher the accessibility, the closer the intercity connectedness. [ABSTRACT FROM AUTHOR]

A study of the accessibility of a city's scenic spots via different travel modes can contribute to optimization of tourism-related transportation while improving tourists' travel-related satisfaction levels and advancing tourism. We systematically analyzed the accessibility of 56 scenic spots in Xi'an City, China, via car and public transport travel modes using the real-time travel function of the Baidu Maps API (Application Programming Interface) along with spatial analysis methods and the modal accessibility gap index of scenic spots. We obtained the following results. First, maximum and minimum travel times using public transport exceeded those using cars. Moreover, the accessibility of scenic spots via cars and public transport presented a circular spatial pattern of increasing travel time from the center to the periphery. Contrasting with travel by public transport, car travel showed a clear time-space compression effect. Second, accessibility of the scenic spots via cars and public transport showed some spatial heterogeneity, with no clear advantages of car accessibility in the central urban area. However, advantages of car accessibility were increasingly evident moving from the center to the periphery. Third, whereas the correlation of the modal accessibility gap index of scenic spots in Xi'an with global space was significantly positive, local spatial interdependence was only evident in some inner city areas and in marginal areas. Moreover, spatial heterogeneity was evident in two regions but was insignificant in other areas, indicating that the spatial interdependence of the modal accessibility gap index in most scenic spots was not apparent in terms of the overall effect of public transport routes, road networks, and the distribution of scenic spots. The improvement of public transport coverage in marginal areas and the optimization of public transport routes in central urban areas are essential tasks for improving travel using public transport in the future. [ABSTRACT FROM AUTHOR]

In response to challenges caused by high gasoline prices, traffic congestion, and greenhouse gas emissions, smart internment on intercity rail transit infrastructures and service suggests a rekindling of many countries' interest in offering a range of benefits over automobile travels. In order to check the suitability of the proposed intercity rail transit system with the local conditions in a region, models for relating the intercity rail transit scope and social economy factors have been developed with the datasets obtained in the Pearl River Delta (PRD) region in Guangdong Province, China. In this paper, the accessibility-based approach is presented to explore the impact of the intercity rail transit system planning on the regional development. The impact of three typical accessibility variables, transportation, population, and economic accessibilities, are considered in the approach. The global rail transit scope planning models are developed by using the regression technique to correlate the lengths of 254 regional intercity rail transit systems in different countries in the world with social economy factors. Those models are used for estimating the intercity rail transit size for the PRD region. The modeled transit scopes are examined with spatial distributions of the defined three accessibilities at each node (or centroid center of a town) in a Geographic Information System environment. The developed method has been proven helpful to understanding the gap between transport supply and potential travel demand and the suitability of each node to alignment of each rail transit route through the PRD region case study. [ABSTRACT FROM AUTHOR]

As an important branch of human geography, transportation geography has experienced three periods of evolution: foundation, systematization, and rapid development of the discipline. It has gradually become a relatively mature discipline. During the period 1930-1980, the development of transportation geography consisted mainly of the publication of theoretical texts. During 1980-2000, it gradually became a systematic discipline. Since the start of the 21st century, transportation geography has focused mainly on exploring the impacts of transportation on socio-economic development. Currently, studies on transportation geography have led to significant developments in a number of areas, including transportation theory, facility distribution and planning, transportation flows and network analysis, evaluation of transport modes, transportation planning, and simulation and assessment of urban transportation. Such studies have also enriched human geography research, provided a wider geographical overview and elucidated the development mechanism of transportation, as well as helped to understand the impacts of transport development on socio-economic systems. Some findings obtained by geographers have been widely used in transportation geography and related fields, including the four basic laws of transportation generation, the hub-spoke mode of transport organization, the subordinating and guiding functions of transportation on socio-economic development, regional transport dominance measures, accessibility measures, and spatial organization of port systems. [ABSTRACT FROM AUTHOR]

Taking Guangzhou as a case, this paper adopted a questionnaire survey to gather first-hand data and analyzed the characteristics and influencing factors of private car travel in Chinese cities. As the research indicated, trip purposes of private car travel are mainly commute and business affairs with a more flexible trip in the urban core area. And trip intensities are concentrated in a certain extent, with trip frequency being lower in the urban core area than the peripheral area. In addition, the trip time has two significant peaks occurring in the morning and afternoon, and one trough in the midday. And trip spatial distribution is mainly within commute with both residence and employment in urban area and inward commute with residence in suburban area while employment in urban area. Both kinds of commutes direct to the urban area. The study also shows that the characteristics of private car travel are principally influenced by two aspects: travelers’ attributes and urban characteristics. The main travelers’ social and economic attributes influenced it include the gender, education attainment, age, driving experience and per capita monthly household income. The urban characteristics influenced it mainly cover the land use pattern, public traffic facilities and spatial attributes of residential environment. [ABSTRACT FROM AUTHOR]

In order to give an in-depth understanding of the contradictions arising from the land resource supply and demand, this study selected 30 provinces (some are autonomous regions or municipalities) in China to be the research unit, used the carbon emission as an undesirable output, and adopted the Super-SBM DEA model and ESDA-GWR method to research the evolution characteristics and influencing factors of land use efficiency in China in 2003-2013. The results indicated that: (1) The land use efficiency in China overall was moderately ineffective and the overall utilization level was low; (2) The Global Spatial Autocorrelation was instable and had maintained a high level; (3) The "hot spots" mainly being distributed in the southeast coastal regions and "cold spots" being found in the central and western regions, so that as time goes on, the pattern of "high in the east and low in the west" has been gradually formed and stabilized. (4) The GWR model analysis showed that the natural factors such as NDVI, DMSP/OLS and DEM have a significant impact on land use efficiency, thereby providing an important contribution to this study. For the eastern coastal areas, the emphasis should be improving their OT, PF and PGDP, for the western region, should focus on improving its comprehensive economic development level to improve the DMSP/OLS, while strengthening the ecological environment to improve the level of NDVI. [ABSTRACT FROM AUTHOR]