Automotive air pollution : issues and options for developing countries

Air pollution constitutes an ominous threat to human health and welfare. Its adverse effects are pervasive and may be disaggregated at three levels: (a) local, confined to urban and industrial centers; (b) regional, pertaining to transboundary transport of pollutants; and (c) global, related to build up of greenhouse gases. These effects have been observed globally but the characteristics and scale of the air pollution problem in developing countries are not known; nor has the problem been researched and evaluated to the same extent as in industrialized countries. Air pollution, however, can no longer be regarded as a local or a regional issue as it has global repercussions in terms of the greenhouse effect and depletion of the ozone layer. This paper discusses the contribution of motorized land transport to air pollution problems, with special reference to developing countries. It assesses the adverse effects of air pollution from transport sources, primarily motor vehicles, and reviews possible approaches to bring about improvements. The paper identifies key issues and research needs related to land transport and air pollution in developing countriesTransport and Environment,Environmental Economics&Policies,Montreal Protocol,Energy and Environment,Roads&Highways

Sustainable Rural Roads for Livelihoods and Livability

AbstractOf some 33.8 million km. of classified roads that girdle the globe, nearly all unsealed roads and an estimated 85% of paved roads are low-volume roads (LVRs) with ADT of less than 1000 vehicles/day. Rural LVRs have a critical role in economic growth and poverty reduction, and a prominent function in emergency preparedness, disaster relief and rural job creation. This paper discuses the meaning of sustainability and its more practical subset--livability, in relation to rural roads and how the application of context sensitive solutions could help achieve a better balance among the economic, social, and environmental dimensions of sustainability

The study of housing preferences of the Seletar community in Johor Bahru, Malaysia

Johor Johor Bahru, in the state of Johor, is located at the southern tip of Peninsular Malaysia and considered to be one of the most rapidly developing cities in Asia. The land resources of Johor Bahru is financially attractive to both local or foreign investors because of its emergent economic corridor, that is being led by the Iskandar Regional Development Authority (IRDA). The impacts of rapid development in this economic corridor has affected some of its Indigenous community groups, especially the Orang Seletar community. The Orang Seletar people, sea nomads of the Tebrau Strait shores, have been particularly exposed to cultural decay due to the surrounding rapid urbanization. This paper aims to consider the Orang Seletar’s culture and housing typology preferences to inform options for their future housing design consideration and to ensure their cultural sustainability. The first objective of the research is to examine culture and daily activities that were and continue to be practiced by the Orang Seletar, who used to live in houseboats and thus integral to their sea nomadic lifestyle. The second objective is to investigate the typology of the housing settlement patterns of the Orang Seletar community, and the third objective is to assess the housing settlement preferences of the Orang Seletar community. This research uses both qualitative and quantitative approaches, where content analysis of literature is utilised to achieve the first objective. Field observation and survey questionnaires techniques were used to achieve the second objective, and a structured interview was carried out to achieve the third objective. Three types of houses were identified in eight selected villages studied including: single storey landed brick houses that are built on the land by government; houses on stilts that are made of timber; and, lastly, raft houses that float on sea and reverine water. Based on this comparative study, it is concluded that the Orang Seletar people preferred to continue to live on raft houses

Factors Influencing the Transferability of Maintenance Standards for Low-Volume Roads

Among the many parameters that influence the selection of maintenance strategies for unpaved roads, two factors have been selected in this paper to illustrate that caution needs to be exercised when attempting to transfer policies or standards from one set of conditions to another. These two factors are factor costs (not budgets) and material resources. Broadly speaking, the definition of a maintenance policy for an unpaved network implies that besides routine activities such as vegetation control and ditch and culvert cleaning, consideration should be given to the frequency of grading and also to the timing of graveling operations. Drawing from the experience collected in two widely different environments, one in the equatorial forest region of central Africa-where maintenance costs are high and gravel resources scarce-and the other in northeast Brazil, it is shown that maintenance standards are highly dependent not only on traffic volume but also on the properties of surfacing materials and the unit cost of grading. As shown and explained in this paper, the optimum grading frequency derived from economic analyses for a given volume of traffic may vary by a factor of 5, ranging between 2 and 10 times per year. Similarly, the threshold value of traffic volume at which surfacing an earth road with gravel becomes economically justified can range from below 20 to more than 100 vehicles per day, depending on cost of graveling and physical properties of the subgrade to be graveled. Such wide variations suggest the need for a careful definition of local conditions before an attempt is made to transfer maintenance standards across countries or even across regions within a country. Even under the best maintenance policy, vehicle operating costs on unpaved roads are usually 10 to 30 percent higher than those on well-maintained paved roads, mostly because of differences in average surface roughness conditions. Furthermore, the neglect of maintenance on an unpaved network may cause vehicle operating costs to increase by a factor of 2 to 3, because roughness can rise quickly from 5 m/km international roughness index (IRI) (on a newly graded road) to upward of 20 m/km within a few weeks if traffic volume is high. On paved roads, the situation is different: not only is the rate of progression of roughness slower, but also a smalle~. range of values is observed between a pavement in good condition (IRI = 3) and the same pavement at the end of its useful life, that is, in poor condition (IRI = 6 to 8), with the difference in vehicle operating costs generally not more than 30 percent. Therefore, maintaining a network of unpaved roads requires relentless attention as well as a well-defined program of recurrent activities in order to keep the level of service of the roads within acceptable limits. Among the recurrent activities to be carried out, grading and graveling operations are the primary maintenancerelated determinants of road conditions, and in tum of the cost of operating vehicles. The World Bank, 1818 H St. N.W., Washington, D.C. 20433. The frequency at which bladings are to be performed and the timing at which an unpaved road is to be surfaced or resurfaced with gravel constitute the basic requirements of any rationally designed maintenance program, and methods are now available that enable the definition of optimum standards both for grading frequencies and for appropriate timing of gravel surfacing (1-3). However, these standards are strongly dependent upon local conditions and a number of parameters such as traffic, level of service required, the importance of the road, climate (in particular, rainfall), budget constraints, material resources, and unit costs of grading and graveling. In this paper, the effect of the last two parameters is evaluated. EFFECT OF MATERIAL RESOURCES ON MAINTENANCE STANDARDS Grading Frequency Depending on the availability of materials, the wearing course of unpaved roads may consist of a wide variety of soils, ranging from fine-grained silts or clays to fairly coarse gravel. Although the rate of surface deterioration is mostly influenced by traffic volumes, roughness progression is also governed by the physical and geotechnical properties of the surfacing material, that is, its particle size distribution and plasticity

Analysis of Motivation Level of L2 Learners in Enhancing Speaking Skill

The present study focuses on the second language (L2) learners’ motivation as a substantial factor for enhancing speaking skills at the graduate level. Motivation in L2 learning is a complex phenomenon that had gained the attention of researchers and theorists for many decades. Motivation to learn English as a second language have been described and categorized in several ways. However, the emerging trend of English language learning at a high rate calls forth to answer the question such as why learners are so ambitious to learn this language in the presence of a national language. Secondly, if they are learning the English language, what is the kind of motivation urging them to learn it. At the present scenario, the English language has become a compulsion in both academic and professional career of L2 learners; though, the L2 learners should be reinforced to speak in English inside and outside of the classroom. The hegemony of the English language cannot be refuted at any cost because it has been employed in the domains of power-administration, military, education, and commerce since the making of Pakistan. A random sample of hundred graduate students from University of Management and Technology and hundred from University of Education, Lahore were selected. The close-ended questionnaire was used and total numbers of items were 21. The data were analyzed quantitatively using the content analysis method which suggested that the majority of respondents agreed with the notion that learners motivate them to speak in the target language and they were well- known about the significance of English in Pakistan, despite the fact that English is used as a subject in the ESL context rather than as a language. At last, it can be ensured that the study might be utilized for both the L2 learners and in the same sociological conditions. The study ends with the suggestion that English language teaching curricula and teaching strategies should be designed keeping in view the type of motivation (instrumental motivation) which is driving the Pakistani learners

Re-exposure to beta cell autoantigens in pancreatic allograft recipients with pre-existing beta cell autoantibodies

Re-exposure to beta cell autoantigens and its relevance in the presence of donor-specific antibodies (DSA) in pancreatic allograft recipients is not well known. Thirty-three patients requiring a pancreas transplant were enrolled in an IRB approved study. They underwent prospective monitoring for DSA and beta cell autoantibody (BCAA) levels to GAD65, insulinoma-associated antigen 2 (IA-2), insulin (micro-IAA [mIAA]), and islet-specific zinc transporter isoform-8 (ZnT8). Twenty-five (75.7%) had pre-transplant BCAA. Twenty had a single antibody (mIAA n = 15, GAD65 n = 5); five had two or more BCAA (GAD65 + mIAA n = 2, GAD65 + mIAA+IA-2 n = 2, GA65 + mIAA+IA-2 + ZnT8 = 1). No changes in GAD65 (p > 0.29), IA-2 (>0.16), and ZnT8 (p > 0.07) were observed between pre-transplant and post-transplant at 6 or 12 months. A decrease in mIAA from pre- to post-6 months (p < 0.0001), 12 months (p < 0.0001), and from post-6 to post-12 months (p = 0.0002) was seen. No new BCAA was observed at one yr. Seven (21.0%) developed de novo DSA. The incidence of DSA was 24% in patients with BCAA vs. 25% in patients without BCAA (p = 0.69). Pancreatic allograft function of patients with vs. without BCAA, and with and without BCAA + DSA was comparable until last follow-up (three yr). Re-exposure to beta cell autoantigens by pancreas transplant may not lead to increased levels or development of new BCAA or pancreatic allograft dysfunction

Dynamic prediction of survival via Landmark method using the asthma prevention trial in young children

This paper focuses on the applications of Landmark method for obtaining dynamic predictions of survival by using Landmark approach to the data of asthma prevention trial in young children. This work focuses on the different ways to model recurrent events by considering various time scales according to how subjects in the dataset experienced multiple events. Landmark models can be used to dynamically estimate the effect of treatments effects whilst also taken into consideration the history of previous asthma attacks. Our analysis show that the treatment effect should be modelled with a time varying effect and the effect of the previous attack reduces with the passage of time.Scopu