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Small scale producers in developing countries lack easy access to efficient logistics services. They are faced with long distances from both domestic and international markets. Unless they consolidate their trade volumes they face high costs which diminish their ability to trade. However, the process of consolidation is not without cost nor does it occur on its own accord. As a result, the consolidation is typically handled by intermediaries. Using case studies of sisal and soybean supply chains in Brazil and India respectively, this study explores the role and impact of intermediaries in facilitating trade in lagging regions. The study assesses the horizontal relationships between the small scale producers in thin markets and the vertical connections between different tiers of the same supply chain. The study analyzes the traditional approach to linking producers namely through cooperatives and itinerant traders and the relatively newer innovations using ICT. The study finds that farmers linked through the different mechanisms are more integrated to international supply chains or are able to better manage supply chains longer than would otherwise be the case. Intermediaries play several roles including providing transport services and facilitating market exchanges, payments, risk sharing and quality improvements. Generally, information technology driven innovations make it easier to integrate adjacent steps in the value chain. This report on logistics performance at the sub-national level is an on-going endeavour. Similar analysis is being carried out in some countries in Africa to identify the evolving role of intermediaries in low income regions. The results will be developed into a major publication on this topic, with recommendations on how development agencies, civil society and the private sector can improve the design of strategies to reduce logistics costs in low income areas.

In the lane-based signal optimization model, permitted turn directions in the form of lane markings that guide road users to turn at an intersection are optimized with traffic signal settings. The spatial queue requirements of approach lanes should be considered to avoid the overdesigning of the cycle, effective red, and effective green durations. The point-queue system employed in the conventional modeling approach is unrealistic in many practical situations. Overflow conditions cannot be modeled accurately, while vehicle queues are accumulated that block back upstream intersections. In a previous study, a method was developed to manually refine the traffic signal settings by using the results of lane-based optimization. However, the method was inefficient. In the present study, new design constraint sets are proposed to control the effective red and effective green durations, such that traffic enters the road lanes without overflow. The reduced cycle times discharge the accumulated vehicles more frequently. Moreover, queue spillback and residual queues can be avoided. One of the most complicated four-arm intersections in Hong Kong is considered as a case study for demonstration. The existing traffic signal settings are ineffective for controlling the observed traffic demand, and overflow occurs in short lanes. The optimized traffic signal settings applied to the proposed optimization algorithm effectively avoided traffic overflow. The resultant queuing dynamics are simulated using TRANSYT 15 Cell Transmission Model (CTM) to verify the proposed model. The model application is extended to handle the difficult residual queue scenario. It is found that the proposed model can optimize the traffic signal settings in cases where there are short initial residual queues.

The study was aimed to design the landscape on the sides of Baghdad-Babel road and landscaping the aspects of this section of the road length of 1 km, which represents the main entrance of the province of Babel, which is the municipality of Alexandria to achieve the strategy of beautiful roads through the appropriate selection of types of vegetation and emphasis on local species and adapted to environment and soil, which is one of the main factors in the conservation of vegetation on the sides of the roads, as well as the preparation of a design proposal for a rest area on the right side of the section of the road under study to an area of 270,14.108 m2 is not intended for any future use, its currently used by drivers of heavy and medium vehicles and the regular vehicles and passengers while waiting at the entrance to the province of Babylon and provide an opportunity to reduce stress and fatigue on the driver and management of travel requirements and improve traffic safety by reducing traffic accident rates as a result of traffic density in this way.

Invasive alien species (IAS) cause environmental and economical problems. How to effectively manage all IAS at a large area is a challenge. Hypotheses about IAS (such as the “human activity” hypothesis, the “biotic acceptance” and the “biotic resistance”) have been proposed from numerous studies. Here the state of Alabama in USA, widely occupied by IAS, is used as a case study for characterizing the emergent patterns of IAS. The results indicate that most IAS are located in metropolitan areas and in the Black Belt area which is a historical intensive land use area. There are positive relationships between the richness of IAS and the change of human population, the species richness and the number of endangered species, as well as the total road length and farmland area across Alabama. This study partially supports the above three hypotheses and provides a general pattern of local IAS. Based on possible processes related with IAS, some implications for strategically managing local IAS are discussed.

In this paper, we discuss the cellular automata simulation of the traffic flow on a two-lane road with a construction zone. The simulation model is based on the cellular automata and the stochastic velocity model. In the stochastic velocity model, the vehicles are controlled with a uniform random number. A two-lane road with a construction zone is considered as the object domains and the simulation results are compared with the results of the one-lane and two-lane roads without a construction zone. Although it has been predicted from the analytical study that the traffic flow on a road with a construction zone depends only on the number of the available lanes, the simulation results shows that the traffic flow depends not only on the number of the available lanes but also the length of the construction zone. 1 Introduction The existing traffic simulation models can be briefly classified into the macroand micro-models [1, 2, 3]. In the macro-model, the traffic flow is considered as the liquid flow and, therefore represented with the constitutive equation. In the micro-model, the movement of each vehicle is simulated with a computer and the emergent phenomenon of driving vehicles shows the traffic flow. Since the computational cost of the macro-model is much lower than that of the micromodel, the macro-model simulation is often adopted for the large-scale traffic simulation in which a large number of vehicles are driving in a wide area. Tanahashi et al. have pointed out that it is very important to represent the different cartelistic feature of each vehicle for more accurate simulation of the traffic flow [3]. So, the authors have focused on the cellular automata model for the Urban Transport XII: Urban Transport and Cellular automata simulation of traffic flow E. Kita, T. Tamaki & H. Shimizu Graduate School of Information Sciences, Nagoya University, Nagoya, Japan Abstract In this paper, we discuss the cellular automata simulation of the traffic flow on a two-lane road with a construction zone. The simulation model is based on the cellular automata and the stochastic velocity model. In the stochastic velocity model, the vehicles are controlled with a uniform random number. A two-lane road with a construction zone is considered as the object domains and the simulation results are compared with the results of the one-lane and two-lane roads without a construction zone. Although it has been predicted from the analytical study that the traffic flow on a road with a construction zone depends only on the number of the available lanes, the simulation results shows that the traffic flow depends not only on the number of the available lanes but also the length of the construction zone. 1 Introduction The existing traffic simulation models can be briefly classified into the macroand micro-models [1, 2, 3]. In the macro-model, the traffic flow is considered as the liquid flow and, therefore represented with the constitutive equation. In the micro-model, the movement of each vehicle is simulated with a computer and the emergent phenomenon of driving vehicles shows the traffic flow. Since the computational cost of the macro-model is much lower than that of the micromodel, the macro-model simulation is often adopted for the large-scale traffic simulation in which a large number of vehicles are driving in a wide area. Tanahashi et al. have pointed out that it is very important to represent the different cartelistic feature of each vehicle for more accurate simulation of the traffic flow [3]. So, the authors have focused on the cellular automata model for the

Concerning social costs, in Japan, many disputants have already argued, so the terminology of social costs has been used generally.,

The current review summarizes the knowledge generated by the recently published studies of the last twenty years, in the field of forest road networks, concerning the impact of forest road construction on hydrological processes. The currently applied methodology techniques/practices are discussed, the findings are highlighted and effective mitigation measures to mitigate the impact of forest roads are proposed. Critical for the minimization of the impact of forest roads on overland flow is the significant decrease in road surface runoff and overland flow velocity. The decrease in runoff energy reduces the detachment of soil particles and transportation in streams. The disturbances of forest roads in logging areas should be limited to decrease soil erosion. Additionally, aiming to minimize sediment transportation into the streams, it is very important to reduce the connectivity between the forest roads (or skid trails) and streams. The positive role of vegetation and organic matter on the road prism, naturally/technically established riparian buffers along the streams, and the use of appropriate bioengineering designs for each area significantly decrease the runoff generation and sedimentation. From a construction point of view, the decrease in short and long-term forest road-related impact could be achieved by reducing the depth of excavations and the use of soil compaction limiting technology during forest works. The road network design should be more efficient, avoiding hydrologically active zero-order basins. Techniques that minimize the length and connectivity among skid trails, unpaved roads and streams are highly crucial. Broad-based dips, immediate revegetation and outsloping of the road base are considered good road construction practices. Research should be focused on the hydrologic behavior of forest road networks and on the impact at the watershed scale, the degree of connectivity, utilizing plenty of qualitative field data, especially during intense rainfall events, which has been proven to exacerbate the runoff and sediment generation and transportation into the stream networks.

Abstract This study modeled changes in sediment delivery to streams in response to systematic Best Management Practice (BMP) upgrades to a 28,000 km forest road network in western Montana and northern Idaho. Key BMPs applied included installing more frequent road drainage features to disperse runoff entering streams, managing public road access to reduce the need for ongoing maintenance, increasing road surface vegetative cover, and installing supplemental filtration near streams. The Washington Road Surface Erosion Model (WARSEM), with locally validated model assumptions, was used to estimate fine sediment delivery before and after BMP upgrades. Results from 10 repeated watersheds (inventoried and modeled before and after BMPs) estimated that sediment delivery (weighted by watershed road length) was reduced by 46% (watershed range: –84% to +57%) over a 10–15-year period. Delivery rates from these watersheds were similar to an additional 22 watersheds that were inventoried after BMP upgrades had been completed. Road sediment delivery from surface erosion estimated by WARSEM in BMP-upgraded watersheds represented less than a 5% increase above background erosion rates in this region.

We provide the first comparative multispecies analysis of spatial genetic structure and diversity in the circumpolar Arctic using a common strategy for sampling and genetic analyses. We aimed to identify and explain potential general patterns of genetic discontinuity/connectivity and diversity, and to compare our findings with previously published hypotheses. We collected and analyzed 7707 samples of 17 widespread arctic–alpine plant species for amplified fragment length polymorphisms (AFLPs). Genetic structure, diversity and distinctiveness were analyzed for each species, and extrapolated to cover the geographic range of each species. The resulting maps were overlaid to produce metamaps. The Arctic and Atlantic Oceans, the Greenlandic ice cap, the Urals, and lowland areas between southern mountain ranges and the Arctic were the strongest barriers against gene flow. Diversity was highest in Beringia and gradually decreased into formerly glaciated areas. The highest degrees of distinctiveness were observed in Siberia. We conclude that large‐scale general patterns exist in the Arctic, shaped by the Pleistocene glaciations combined with long‐standing physical barriers against gene flow. Beringia served as both refugium and source for interglacial (re)colonization, whereas areas further west in Siberia served as refugia, but less as sources for (re)clonization.