Analysis of Global and Regional Changes in Biogeochemical Carbon Cycle: A Spatially Distributed Model

This report presents a view on the current state and perspective of mathematical modeling of global and regional biosphere and climate changes under anthropogenic inputs. A spatial model of carbon cycle in the "Atmosphere -- Plants -- Soil" system is described, and the impact of industrial CO2 emissions, deforestation and soil erosion on the dynamics of the "Atmosphere -- Terrestrial Ecosystems -- Ocean" system is analyzed. The countries' carbon dioxide budget of 1995 is estimated. Consequences of several scenarios of the implementation of the Kyoto Protocol to the UN Framework Convention on Climate change are discussed. The stability of the biosphere and climate are treated from the point of view of the biosphere's ability to compensate anthropogenic inputs. In this context, the issue of the validity of the Le Chatellier principle in the biosphere is considered

Calibration, Validation and Performance Evaluation of Swat Model for Sediment Yield Modelling in Megech Reservoir Catchment, Ethiopia

Intensive agricultural practice in Ethiopian highlands results in increasing rates of soil erosion and reservoir sedimentation. The estimation of sediment yield and prediction of the spatial distribution of soil erosion on the upper Megech reservoir catchment enables the local governments and policymakers to maximize the design span life of the Megech reservoir through implementing appropriate soil conservation practices. For this study, the sediment yield was estimated and analyzed through hydrological modeling (SWAT). The simulated outputs of the model show that the mean annual surface runoff was 282 mm and the mean annual streamflow was 153 m3/s. Similarly, 12.33 t/ha mean annual total sediment load gets into the Megech reservoir. The model performance standard used to evaluate the model result indicates that the model was superior in performing the trend of runoff and sediment yield in both calibration and validation periods. Finally, the most erosion vulnerable sub-basins that could have a significant impact on the sediment yield of the reservoir were identified. Based on this, sub-basin 7, 25, 27, 18 and 29 were found to be the most erosion sensitive areas that could have a significant contribution to the increment of sediment yield in the Megech reservoir. Considering the land use, soil type, slope, and relief of erosion vulnerable sub-basins cut off drains, fallow land, contour ploughing, Fanya juu terraces, soil bunds combined with trenches and trees could be the possible management strategies to reduce the sediment yield in the catchment

A Practical Approach to Safety management of County Roads

Rural roads are well-documented as having a greater traffic fatality rate than urban roads. For medium- and high-volume rural roads with a considerable crash history, previous studies have focused on the identification of high-crash locations. The majority of rural roads in Indiana are low-volume county roads. However, the methods for identifying safety problems on medium- and high-volume roads are often not suitable for county roads. Such methods may result in improper allocation of resources for safety upgrades to only the particular locations which experienced crashes, not necessarily where the crash risk is greatest. For example, there may be hazards on the road right-of-way that have not yet been manifested through crashes, but still represent a considerable risk should they influence the driver’s behavior and/or affect the crash outcome. This study proposes decision-making based on the crash risk and fatality risk on road elements (segments and intersections) estimated from the geometry, pavement, roadside features, and traffic volume (if available). The methodology will be applied to the rural county road network in Tippecanoe County. Once the road elements with the highest risk are identified, the actual crash history will be used to supplement the analysis. The outcome of this study will be implemented as a project-oriented safety management tool for county roads. This approach will identify low-cost safety countermeasures applied to multiple roadway elements which will provide the most benefits under limited resources. The proposed approach will make economic justification of safety improvements on county roads easier than the current method based on high-crash locations

A Practical Approach to Safety Management of County Roads

Rural roads are well-documented as having a greater traffic fatality rate than urban roads. For medium- and high-volume rural roads with a considerable crash history, previous studies have focused on the identification of high-crash locations. The majority of rural roads in Indiana are low-volume county roads. However, the methods for identifying safety problems on medium- and high-volume roads are often not suitable for county roads. Such methods may result in improper allocation of resources for safety upgrades to only the particular locations which experienced crashes, not necessarily where the crash risk is greatest. For example, there may be hazards on the road right-of-way that have not yet been manifested through crashes, but still represent a considerable risk should they influence the driver’s behavior and/or affect the crash outcome. This study proposes decision-making based on the crash risk and fatality risk on road elements (segments and intersections) estimated from the geometry, pavement, roadside features, and traffic volume (if available). The methodology will be applied to the rural county road network in Tippecanoe County. Once the road elements with the highest risk are identified, the actual crash history will be used to supplement the analysis. The outcome of this study will be implemented as a project-oriented safety management tool for county roads. This approach will identify low-cost safety countermeasures applied to multiple roadway elements which will provide the most benefits under limited resources. The proposed approach will make economic justification of safety improvements on county roads easier than the current method based on high-crash locations

Performance Assessment of Road Barriers in Indiana

Road barriers have been used as an effective countermeasure to prevent exposure of errant vehicles to both vehicles travelling in the opposite direction and to roadside hazards. The objective of this study was to evaluate the in-service safety performance of three types of road barriers (concrete barriers, steel W-beam guardrails, and high-tension cable barriers) in Indiana using cross-sectional analysis based on crash data. The quantitative evaluation was comprised of three components: 1) the effect of the road, barrier scenarios, and traffic on the barrier-relevant (BR) crash frequency, 2) the effect of the road and the barrier scenarios on the BR harmful events, and 3) the effect of the BR events and other conditions on the injury outcomes. The introduction of the BR harmful events linked the crash onset with its outcome. The three developed statistical models were connected through their inputs-outputs and followed the sequence of various BR events during the BR crash. This improvement allowed a more comprehensive and insightful analysis of the barriers’ safety effects and a more efficient use of data. The injury outcomes were estimated for all the individuals in a crash rather than for the most severe outcome of a crash. Further improvement of the cost estimates was accomplished by utilizing hospital data. For median barriers, this study found that the total number of BR crashes was higher with the use of median barriers, mostly due to the introduction of collisions with barriers and an increase in the collisions after redirecting vehicles back to traffic. These undesirable effects of barriers were surpassed by the positive results of reducing hazardous events such as cross-median crashes, rollover events, and collisions with roadside hazards, which substantially reduced the number of severe injuries and fatalities. The average (unit) crash costs were estimated for roads without barriers and for roads with various barrier scenarios. The crash costs were reduced by 50% where cable barriers were in medians wider than 50 feet and where concrete barriers or guardrails were in medians less than or equal to 50 feet wide. Roadside barriers (guardrails) reduced the unit crash costs by 20% to 30%. Median cable barriers were found to be the most effective among all the studied barriers due to the smallest increase in the crash frequency and least severe injuries in barrier-relevant crashes. A cable barrier’s offset to the travelled way was also investigated in this study. When considering vehicles moving in one direction, the nearside cable barriers installed at an offset less than or equal to 30 feet performed better than far-side cable barriers with a larger offsets thanks to the better protection they provide for vehicles against rollovers in the median and impact with the median drain. Consequently, the biggest safety benefit can be expected where cables barriers are installed in the median at both edges. The results were implemented through a set of crash modification factors and unit crash costs estimated for 51 road-barrier scenarios. An implementation procedure is provided to quantify the crash costs and the safety benefits for these scenarios

Contextual Factors Impacting School and Pastoralist Family Communication in Rural Mongolia: A Partial Ecological Model

This study developed a partial ecological model of contextual factors impacting school and pastoralist family communication at the primary school level in rural Mongolia based on Bronfenbrenner’s ecological model. To develop the model, we interviewed 10 classroom teachers and 10 pastoralist parents from two remote county schools in eastern Mongolia. During our interpretative phenomenological analysis based on semi-structured interviews, we found eight contextual factors impacting rural school and pastoralist family communication located at the exosystem and the macrosystem levels. The partial ecological model can be used in teacher education programs providing a greater insight into the contexts of school-family communication for pre-service and in-service teachers and for teacher educators and policy makers. The model could also be a foundational model for communication training in teacher education courses. In this respect, the current study may help inform researchers and education policy makers not only in Mongolia but also in other settings