Street-canyon ventilation and pollutant removal estimate

The correlations among air exchange rate (ACH), pollutant exchange rate (PCH) and friction factor (f) are proposed to evaluate the performance of ventilation and pollution removal of street canyons of different building-height-to-street-width (aspect) ratios (ARs) and building shapes in this paper. Hypothetical urban areas were simplified to computational domains consisting of idealized two-dimensional (2D) street canyons and the Reynolds-averaged Navier-Stokes (RANS) equations with the Renormalization Group (RNG) k-є turbulence model were adopted in the mathematical modelling. It is found that the turbulent components of ACH and PCH are closely related to f while their mean components are rather extraneous.postprin

Rethinking Sustainable Mobility: Understanding the use of boda-boda motorcycle taxis in Kampala, Uganda

Cities in Sub-Saharan Africa are characterised by informal transportation services compensating for the lack of institutionalised transportation system. In Kampala, Uganda, the vast army of boda-boda (boda) motorcycle taxis have proliferated through the city, with passengers and/or cargo goods straddled behind the boda drivers as they navigate through the city’s congested and dilapidated roads. Despite the strong presence of informal transport in developing cities, local governments often regulate against them as they do not fit the desired modern image. Against this backdrop, the dynamics of the system, perception and needs of the users themselves are neglected and unknown. Therefore, this study aims to identify the role of informal mobility in the sustainable urban landscape by investigating the boda sector in Kampala from the users’ (i.e. passengers and cargo) lens. Qualitative Geographical Information System (GIS) as a mixed-methods approach was adopted for the research, explicitly: GIS analysis, questionnaire surveys, interviews, and unstructured observations. The study develops understanding of the boda demand – travel patterns, trip purposes, profiles, perceptions, and aspirations of the boda users. Visual representations and findings are discussed vis-à-vis the sustainable mobility dimensions. The study finds that the boda physical attributes influence the types of market served including service areas and users. More importantly, the boda market morphs according to the city’s prevailing activities throughout the day, signifying how bodas are woven into the urbanites’ life and the city itself. This is more distinctive for lower income groups, working population, and areas with high formal and informal economic activities. Nonetheless, the high social costs resulting from unprofessional driving and high accident rates should justify intervention by formal and informal institutions. Overall, this study identifies the complementary role of the boda system and advocate for its integration into the public transport system through three transition pathways, namely improvement, complementary planning, and institutional reform. This analysis suggests that the informal mobility system and users should be engaged in changing the negative narratives of the sector and working towards sustainable urban mobility and development

Multi-Stream Saline-Jet Dissection Using a Simple Irrigation System Defines Difficult Tissue Planes

A readily available, low-cost technology is described to assist in dissecting difficult tissue planes

Total knee arthroplasty for primary knee osteoarthritis: Changing pattern over the past 10 years

Objective: To review the epidemiology of total knee arthroplasty for primary osteoarthritis and the change of patient characteristics over the last decade. Design: Retrospective review. Setting: A tertiary referral centre for joint replacement surgery in a teaching hospital in Hong Kong. Patients: All patients who underwent primary total knee arthroplasty for primary knee osteoarthritis from January 2000 to December 2009. Results: In all, 1157 total knee arthroplasties (589 left and 568 right) were performed on 588 females and 162 males. The annual number of total knee arthroplasties increased from 91 in 2000 to 181 in 2009. The annual number of patients increased from 58 (46 female, 12 male) in 2000 to 159 (117 female, 42 male) in 2009. When compared yearly results, there were no significant changes in the preoperative Knee Society Knee Score, Knee Society Functional Assessment, and passive range of motion of these patients. However, there was a significant decreasing trend with regard to lower limb mechanical axis mal-alignment, from 15.1° deviation from the neutral axis in 2000, to 14.8° deviation in 2004, and then 12.9° deviation in 2009 (mostly varus deformity). There was no difference between left knees and right knees, and between females and males. The mean age of the patients did not show significant change over the past decade, but the number and proportion of patients over 80 years old showed an increase from 4.8% (2000 to 2004) to 13.8% (2005 to 2009). On the other hand, the number and proportion of patients under the age of 60 years did not change. Conclusions: There was an increasing trend towards total knee arthroplasties, both in terms of number of operations and patients. The number of younger patients having total knee arthroplasty did not increase over the last 10 years, whereas the number of those older than 80 years increased significantly over that period.published_or_final_versio

Factors influencing young men's decision to undergo health screening in Malaysia: a qualitative study

Objectives: Uptake of health screening is low in men, particularly among those aged <40 years. This study aimed to explore factors that influence health screening behaviour in younger men. Design: This qualitative study employed an interpretive descriptive approach. Two trained researchers conducted in-depth interviews (IDIs) and focus group discussions (FGDs) using a semi-structured topic guide, which was developed based on literature review and behavioural theories. All IDIs and FGDs were audio-recorded and transcribed verbatim. Two researchers analysed the data independently using a thematic approach. Participants and setting: Men working in a banking institution in Kuala Lumpur were recruited to the study. They were purposively sampled according to their ethnicity, job position, age and screening status in order to achieve maximal variation. Results: Eight IDIs and five FGDs were conducted (n=31) and six themes emerged from the analysis. (1) Young men did not consider screening as part of prevention and had low risk perception. (2) The younger generation was more receptive to health screening due to their exposure to health information through the internet. (3) Health screening was not a priority in young men except for those who were married. (4) Young men had limited income and would rather invest in health insurance than screening. (5) Young men tended to follow doctors' advice when it comes to screening and preferred doctors of the same gender and ethnicity. (6) Medical overuse was also raised where young men wanted more screening tests while doctors tended to promote unnecessary screening tests to them. Conclusions: This study identified important factors that influenced young men's screening behaviour. Health authorities should address young men's misperceptions, promote the importance of early detection and develop a reasonable health screening strategy for them. Appropriate measures must be put in place to reduce low value screening practices

A Content-based search engine on medical images for telemedicine

Retrieving images by content and forming visual queries are important functionality of an image database system. Using textual descriptions to specify queries on image content is another important component of content-based search. The authors describe a medical image database system MIQS which supports visual queries such as query by example and query by sketch. In addition, it supports textual queries on spatial relationships between the objects of an image. MIQS is designed as a client-server application in which the client accesses the database and its images via the WWW.published_or_final_versio

Parameterisation of flows and pollutant transport over idealised urban roughness

No. J7.2Atmospheric flow over urban areas basically is a type of turbulent flow over roughness. The flows and pollutant transport process, especially at the lower part of the boundary layer (BL), is strongly modified due to the presence of building geometry. The aerodynamic resistance exerted by the surface roughness reduces the mean velocity in the lower BL but enhances the turbulence intensity. Moreover, the near-wall impingement structures over rough surfaces are attributed to the flow dynamics aloft, leading to increasing aerodynamic resistance and BL depth. However, the dependence on surface morphology and BL depth is not yet well understood. There is ...postprin

A theory on the ventilation over hypothetical urban areas

Urban roughness is one of the major factors affecting the flows and turbulence structures in the bottom of the atmospheric boundary layer (ABL). Whereas, our understanding of their relation is limited. In this paper, we attempt to examine the interaction among aerodynamic resistance (friction factor f), ventilation (air exchange rate ACH), and pollutant removal (pollutant removal rate PCH). Using the method of characteristic, analytical solution shows that the turbulent ventilation of a hypothetical urban area is directly proportional to the square root of friction factor (ACH? f1-2) regardless of the building geometry. Next, a series of computational fluid dynamics (CFD) sensitivity tests are performed to verify the theory. In addition to the commonly employed rectangular building mod...published_or_final_versio