Going carless in different urban fabrics : socio-demographics of household car ownership

Diverse physical features of urban areas alongside socio-demographic characteristics affect car ownership, and hence the daily mobility choices. As a case of sustainable mobility, we explore how various urban environments and socio-demographics associate with the spatial and social distribution of household car ownership and carlessness in the Helsinki Metropolitan Area, Finland. Three urban fabrics characterizing the study area are established based on the transportation mode (walking, public transportation, or automobile) the physical urban environment primarily supports. The national level Monitoring System of Spatial Structure and Urban Form database, and the National Travel Survey (2016) are utilized to further include spatial and socio-demographic variables into our analysis across these fabrics. Our results show that households with and without cars differ in terms of residential distance to the city center, neighborhood density, house type, and socio-demographic profiles. Single pensioners and students are most likely to be carless, whereas families represent the opposite. Within the carless households the differences are also evident between different groups. For the more affluent households residing in dense and well-connected areas, and mostly possessing driver's licenses, carlessness is presumably a choice. Contrarily, many other carless households represent the less affluent often located in the more distant, low-density, and less accessible areas, while also possessing less driver's licenses, making carlessness more of a constraint, as the local urban fabric does not support such lifestyle. Consequently, carless households should be increasingly recognized as a focus group in sustainable urban planning in terms of identifiable best practices and potential vulnerability.Peer reviewe

Going carless in different urban fabrics: socio-demographics of household car ownership

Diverse physical features of urban areas alongside socio-demographic characteristics affect car ownership, and hence the daily mobility choices. As a case of sustainable mobility, we explore how various urban environments and socio-demographics associate with the spatial and social distribution of household car ownership and carlessness in the Helsinki Metropolitan Area, Finland. Three urban fabrics characterizing the study area are established based on the transportation mode (walking, public transportation, or automobile) the physical urban environment primarily supports. The national level Monitoring System of Spatial Structure and Urban Form database, and the National Travel Survey (2016) are utilized to further include spatial and socio-demographic variables into our analysis across these fabrics. Our results show that households with and without cars differ in terms of residential distance to the city center, neighborhood density, house type, and socio-demographic profiles. Single pensioners and students are most likely to be carless, whereas families represent the opposite. Within the carless households the differences are also evident between different groups. For the more affluent households residing in dense and well-connected areas, and mostly possessing driver's licenses, carlessness is presumably a choice. Contrarily, many other carless households represent the less affluent often located in the more distant, low-density, and less accessible areas, while also possessing less driver's licenses, making carlessness more of a constraint, as the local urban fabric does not support such lifestyle. Consequently, carless households should be increasingly recognized as a focus group in sustainable urban planning in terms of identifiable best practices and potential vulnerability

Associations of neighborhood-level socioeconomic status, accessibility, and quality of green spaces in Finnish urban regions

Highlights • Fair access to green spaces with varying qualities was analyzed in Finland. • Most of the Finnish urban population lives within 300 m from any green space. • Large green areas and forests were more accessible to high SES areas. • Green areas with facilities and routes were more accessible to low SES areas. • Quality of green spaces should be better considered in accessibility analyses. Abstract Ensuring fair access to urban green spaces is a constant challenge for planning in densifying cities. Moreover, the quality of green spaces that determines their usability is often insufficiently considered in accessibility research. We examined residents’ accessibility to different types of green spaces also by neighborhood-level socioeconomic status (SES) in the seven largest urban regions in Finland. We identified eight different green space types, and high and low SES neighborhoods using income, education, and unemployment rate. We calculated network-based accessibility to the different types of green spaces and compared areas with a high and low SES using ANOVA. 90% of the urban residents lived within 300 meters of any green space. However, inclusion of the quality factors decreased accessibility of the green spaces from 34% to 75%. Residents living in high and low SES areas had different quality features in their nearest green spaces. Recreation facilities and routes were closer to low SES areas, whereas areas of high SES were associated with better accessibility to large green areas, and forests. This pattern recurred in most individual cities with varying distance differences. Our results emphasize the importance of considering the quality of green spaces in urban planning

Bath concentration of anionic contrast agents does not affect their diffusion and distribution in articular cartilage in vitro

Objective: Differences in contrast agent diffusion reflect changes in composition and structure of articular cartilage. However, in clinical application the contrast agent concentration in the joint capsule varies, which may affect the reliability of contrast enhanced cartilage tomography (CECT). In the present study, effects of concentration of x-ray contrast agents on their diffusion and equilibrium distribution in cartilage were investigated. Design: Full-thickness cartilage discs (d = 4.0 mm, n = 120) were detached from bovine patellae (n = 24). The diffusion of various concentrations of ioxaglate (5, 10, 21, 50 mM) and iodide (30, 60, 126, 300 mM) was allowed only through the articular surface. Samples were imaged with a clinical peripheral quantitative computed tomography scanner before immersion in contrast agent, and after 1, 5, 9, 16, 25, and 29 hours in the bath. Results: Diffusion and partition coefficients were similar between different contrast agent concentrations. The diffusion coefficient of iodide (473 ± 133 μm2/s) was greater (P ≤ 0.001) than that of ioxaglate (92 ± 46 μm2/s). In full-thickness cartilage, the partition coefficient (at 29 h) of iodide (71 ± 5%) was greater (P ≤ 0.02 with most concentrations) than that of ioxaglate (62 ± 6%). Conclusions: Significant differences in partition and diffusion coefficient of two similarly charged (-1) contrast agents were detected, which shows the effect of steric interactions. However, the increase in solute concentration did not increase its partition coefficient. In clinical application, it is important that contrast agent concentration does not affect the interpretation of CECT imaging

Transport of iodine is different in cartilage and meniscus

Contrast enhanced computed tomography (CECT) has been proposed for diagnostics of cartilage and meniscus injuries and degeneration. As both tissues may be imaged simultaneously, CECT could provide a method for comprehensive evaluation of knee joint health. Since the composition and structure of cartilage and meniscus are different, we hypothesize that transport characteristics of anionic contrast agents also differ between the tissues. This would affect interpretation of CECT images and warrants investigation. To clarify this, we aimed to determine the transport kinematics of anionic iodine (q\ua0=\ua0−1, M\ua0=\ua0126.9\ua0g/mol), assumed to not be significantly affected by the steric hindrance, thus providing faster transport than large molecule contrast agents (e.g., ioxaglate). Cylindrical samples (d\ua0=\ua06\ua0mm, h\ua0=\ua02\ua0mm) were prepared from healthy bovine (n\ua0=\ua010) patella and meniscus, immersed in isotonic phosphate-buffered NaI solution (20\ua0mgI/mL), and subsequently imaged with a micro-CT at 20 time points up to 23\ua0h. Subsequently, normalized attenuation and contrast agent flux, as well as water, collagen, and proteoglycan (PG) contents in the tissues were determined. Normalized attenuation at equilibrium was higher (p\ua0=\ua00.005) in meniscus. Contrast agent flux was lower (p\ua0=\ua00.005) in the meniscus at 10\ua0min, but higher (p\ua