1,721,073 research outputs found
A comparative economic assessment of urban transport infrastructure options in low- and middle-income countries
No full textThe dominance of motorcycles in mixed transport systems in developing cities and countries might lead to several problems such as traffic congestion and accident. To solve these challenges and increase the modal share of public transport (PT), several new PT projects have been invested in these countries. However, there seems to be very little evidence on evaluation methods of all transport modes to analyse the feasibility of a new PT mode and identify the most cost-effective mixed transport system. Therefore, it is essential to have a comprehensive evaluation method for motorcycle, car, Demand Responsive Transit (DRT) and PT in mixed transport environments. Hence, the main aim of this thesis is to develop a comparative economic assessment for evaluating the feasibility of a new PT mode and choosing the best mixed transport system based on the PT technologies’ characteristics and the conditions of local transport networks. The comparative economic assessment is integrated from four models: Social Cost Model, Incremental Elasticity Analysis, Incremental Multinomial/Nested Logit Model and Microscopic Simulation Model. The Social Cost Model calculates the social costs of exclusive private transport (PRV), segregated PT, exclusive DRT and mixed transport at a strategic planning level. The Incremental Elasticity Analysis evaluates endogenous changes in total general demand of all transport modes by using the demand elasticity with respect to a composite cost (a logsum). The Incremental Multinomial/Nested Logit Model estimates the choices of passengers in favour of all transport modes with respect to generalised costs. The Microscopic Simulation Model simulates all existing transport modes’ flows on the local network by using a microscopic simulation model in VISSIM, which is developed, calibrated and validated based on the data collected from one real urban corridor in Hanoi, the capital of Vietnam. The comparative economic assessment was applied to compare the existing mixed transport situation and twelve transport infrastructure options with a new PT technology (Bus Rapid Transit, elevated Metro or Monorail) replacing the existing bus services; either wholly or partially, and with or without a congestion charge scheme for PRV on the chosen corridor in Hanoi, in terms of average social cost, total general demand and PT share. The results show that eight options with Bus Rapid Transit or Monorail or Metro are feasible. In addition, the BRT option that replaces all existing buses with a congestion charging scheme is the best alternative in terms of average social cost. Transport planners and decision makers in Hanoi can draw on the findings of this thesis. Moreover, the methodology of the comparative economic assessment might be applied and modified to various transport networks with an abundance of motorcycles to assess the costs and benefits of each new PT technology and mixed transport systems with or without the congestion charge. However, various limitations are identified and further work is suggested
A newspecies of araregenus,Truxonchus quangi sp. n. (Mononchida,Anatonchidae) from Bat Xat nature reserve in Lao Cai Province, Vietnam
No full textVu, Tam T.T. (2021): A newspecies of araregenus,Truxonchus quangi sp. n. (Mononchida,Anatonchidae) from Bat Xat nature reserve in Lao Cai Province, Vietnam. Zootaxa 4985 (2): 253-260, DOI: https://doi.org/10.11646/zootaxa.4985.2.
Description of a new species, Actus hagiangensis (Mononchida, Mylonchulidae) from Ha Giang province, Vietnam
No full textVu, Tam T.T. (2020): Description of a new species, Actus hagiangensis (Mononchida, Mylonchulidae) from Ha Giang province, Vietnam. Zootaxa 4861 (1): 131-138, DOI: https://doi.org/10.11646/zootaxa.4861.1.
A comparative economic assessment of urban transport infrastructure options in low- and middle-income countries
No full textSeveral innovative public transport (PT) projects have been developed in low- and middle-income countries (LMICs), where cars, motorcycles and buses share the facilities. However, there seems to be very little evidence on assessment methods to analyse the feasibility of different PT modes and identify the most cost-effective mixed transport system. To address this issue, this study develops a comparative economic assessment (CEcoA) based on the PT technologies’ characteristics and the conditions of local transport networks. The assessment integrates four models. First, a social cost model (SCM), that calculates the social costs of each mode and mixed transport systems, is the key model in the assessment. Second, an incremental elasticity analysis (IEA) evaluates changes in total demand by using the demand elasticity with respect to a composite cost. The IEA solves the first drawback of the SCM that demand is assumed to be fixed. Third, an incremental logit model (ILM) estimates changes in modal shares with respect to generalised costs. The ILM overcomes the second disadvantage of the SCM, where preferences of users for all alternative transport modes are not considered. Fourth, a microscopic simulation model (MSM) simulates all existing transport modes’ flows on the local network. The MSM solves the third drawback of the SCM, which only considers an isolated corridor without any interaction between the different modes and any junctions. The assessment was applied to compare an existing mixed transport situation and twelve options with an introduction of new PT technologies (Bus Rapid Transit - BRT, elevated Metro and Monorail) replacing the existing bus services; either wholly or partially, and with or without a congestion charge scheme for private transport (PRV) on a corridor in Hanoi, Vietnam in terms of average social cost (ASC), total demand and PT share. The results show that eight options with BRT or Monorail or Metro are feasible, whilst the BRT option that replaces all existing buses and includes congestion charging is the best alternative in terms of ASC. Transport planners and decision makers can draw on the findings of this research. A congestion charge scheme might be considered for the local conditions to meet specific objectives such as a reduction in ASCs and an increase in modal share of PT. The CEcoA can be a strategic tool for not only planning new PT technologies on corridors in the whole network but also retrospectively evaluating investments of PT modes. Moreover, the methodology of the CEcoA might be applied and modified to various transport networks with an abundance of motorcycles to assess the costs and benefits of new PT modes and mixed transport systems with or without the congestion charge
FIGURE 2 in A newspecies of araregenus,Truxonchus quangi sp. n. (Mononchida,Anatonchidae) from Bat Xat nature reserve in Lao Cai Province, Vietnam
No full textFIGURE 2. Holotype female Truxonchus quangi sp.n. A: Holotype female head; B: Amphidial aperture; C: Vulval region with advulval pores; D: Female tail with caudal pores; E: Female entire body; F: Tail terminal (scale bars as indicated).Published as part of Vu, Tam T.T., 2021, A newspecies of araregenus,Truxonchus quangi sp. n. (Mononchida,Anatonchidae) from Bat Xat nature reserve in Lao Cai Province, Vietnam, pp. 253-260 in Zootaxa 4985 (2) on page 257, DOI: 10.11646/zootaxa.4985.2.8, http://zenodo.org/record/494356
FIGURE 1 in Description of a new species, Actus hagiangensis (Mononchida, Mylonchulidae) from Ha Giang province, Vietnam
No full textFIGURE 1. Actus hagiangensis sp. nov. A: Holotype female head region: B: Paratype male head region; C: Female reproductive system; D: Female tail region; E: Male tail region; F: Pharyngo-intestinal junction; G: spicule and gubernaculum (all scare bars 20 µm).Published as part of Vu, Tam T.T., 2020, Description of a new species, Actus hagiangensis (Mononchida, Mylonchulidae) from Ha Giang province, Vietnam, pp. 131-138 in Zootaxa 4861 (1) on page 135, DOI: 10.11646/zootaxa.4861.1.9, http://zenodo.org/record/441467
FIGURE 2 in A newspecies of araregenus,Truxonchus quangi sp. n. (Mononchida,Anatonchidae) from Bat Xat nature reserve in Lao Cai Province, Vietnam
No full textFIGURE 2. Holotype female Truxonchus quangi sp.n. A: Holotype female head; B: Amphidial aperture; C: Vulval region with advulval pores; D: Female tail with caudal pores; E: Female entire body; F: Tail terminal (scale bars as indicated).Published as part of Vu, Tam T.T., 2021, A newspecies of araregenus,Truxonchus quangi sp. n. (Mononchida,Anatonchidae) from Bat Xat nature reserve in Lao Cai Province, Vietnam, pp. 253-260 in Zootaxa 4985 (2) on page 257, DOI: 10.11646/zootaxa.4985.2.8, http://zenodo.org/record/494356
FIGURE 1 in A newspecies of araregenus,Truxonchus quangi sp. n. (Mononchida,Anatonchidae) from Bat Xat nature reserve in Lao Cai Province, Vietnam
No full textFIGURE 1. Holotype female Truxonchus quangi sp.n. A: Female head region: B: Female tail region with caudal glands and pores; C: Vulval region with advulval pores; D: Female tail terminal; E: Female reproductive system (scare bars: A, D = 20 µm; C = 50 µm; D = 40 µm; E = 100 µm).Published as part of Vu, Tam T.T., 2021, A newspecies of araregenus,Truxonchus quangi sp. n. (Mononchida,Anatonchidae) from Bat Xat nature reserve in Lao Cai Province, Vietnam, pp. 253-260 in Zootaxa 4985 (2) on page 255, DOI: 10.11646/zootaxa.4985.2.8, http://zenodo.org/record/494356
FIGURE 2 in Description of a new species, Actus hagiangensis (Mononchida, Mylonchulidae) from Ha Giang province, Vietnam
No full textFIGURE 2. Actus hagiangensis sp. nov. A: Holotype female head; B: Paratype male head; C: Amphidial aperture; D: Female tail; E: Male tail; F: Vaginal region; G: Female reproductive system; H: Spicule and gubernaculum; I: Pharyngo-intestinal junction; J: Tail of aberrant female (scale bars as indicated).Published as part of Vu, Tam T.T., 2020, Description of a new species, Actus hagiangensis (Mononchida, Mylonchulidae) from Ha Giang province, Vietnam, pp. 131-138 in Zootaxa 4861 (1) on page 136, DOI: 10.11646/zootaxa.4861.1.9, http://zenodo.org/record/441467
Figure 2 in Two remarkable new species of the genus Crassolabium Yeates, 1967 from Vietnam (Nematoda: Dorylaimida: Qudsianematidae)
No full textFigure 2. Crassolabium aenigmaticum sp. nov. (female). (A) Entire; (B, C) lip region, in median view; (D) same, surface view; (E) anterior genital branch; (F) uterine egg; (G) posterior portion of pharynx, showing S2O; (H) pharyngeal expansion; (I) cardia; (J) vagina; (K) aberrant or unusual tail, with terminal digitations; (L, M) tail.Published as part of Vu, Tam T., Ciobanu, M., Abolafia, J. & Peña-Santiago, R., 2010, Two remarkable new species of the genus Crassolabium Yeates, 1967 from Vietnam (Nematoda: Dorylaimida: Qudsianematidae), pp. 2049-2064 in Journal of Natural History 44 (33-34) on page 2052, DOI: 10.1080/00222933.2010.481055, http://zenodo.org/record/521026
- …
