• δ 18 O shows seasonality with high values in the summer and low values in the winter. • Precipi... more • δ 18 O shows seasonality with high values in the summer and low values in the winter. • Precipitation isotopic composition is mainly controlled by temperature. • The δ 18 O-T relationship varies seasonally with highest slope in winter. • Dayton gets moisture from Pacific, Gulf of Mexico, Arctic and Continental sources. • δ 18 O from different sources are similar within a season but vary seasonally.
In many cases, there is an irony when regional economic growth is high, but most of the populatio... more In many cases, there is an irony when regional economic growth is high, but most of the population is poor due to the income disparity. The impacts of income disparities on social conflict are the main reasons for doing this research. The panel data regression analysis is used in this research. Therefore, the results show that an increase in income disparity will be followed by a rise in social conflict. Income disparities promote a lower middle group feels unfair and reflect their disappointment in a dysfunctional behavior that deviates from the rules. A group of people who mutually have dysfunctional behavior leads to social conflicts.
A series of major hominin speciation events that took place in East Africa during the Pliocene-Pl... more A series of major hominin speciation events that took place in East Africa during the Pliocene-Pleistocene epochs have been linked to landscape evolution. Previous studies examining the role of climatic and environmental pressures on hominin evolution have used either discontinuous outcrops exposed proximal to, or marine sediments distal from, hominid fossil sites. These sediments have been used to develop stable carbon and oxygen isotope (δ13C, δ18O) proxy-based reconstructions of ancient environments, showing evidence for a series of changes including a transition from woodland to savannah-dominated environments. This work has prompted researchers to hypothesize that speciation events coincided with cooling of the African climate and local aridification during times of glacial intensification. It is speculated that local environmental pressures led to an increase in brain size, breakthroughs in stone technology, and the migration of Homo sapiens out of Africa. However, recent clum...
Much of the Great Miami River Watershed's streams and aquifers in southwestern, Ohio are impacted... more Much of the Great Miami River Watershed's streams and aquifers in southwestern, Ohio are impacted by nitrate contaminants originating from anthropogenic sources. These include synthetic/inorganic fertilizers for agriculture, animal manure, and municipal wastewater. High nitrate concentrations cause ecological disturbances affecting organisms across all trophic levels. Nitrate levels greater than 10 mg/l also pose a danger to human health, if the contaminant reaches drinking water sources. Although networks of water quality monitoring stations in the watershed collect data on nitrate concentrations in surface and groundwater, a nitrate contaminant source has not been identified. In this study we used isotope ratios of nitrogen (δ 15 N) and oxygen (δ 18 O) in nitrates to identify nitrate sources for surface and groundwater. Initially we fingerprinted the isotopic composition of the main nitrate contaminant sources in the watershed. The results show a distinct low δ 15 N for commercial synthetic fertilizers (0.7±4‰) and high δ 15 N for animal and human waste (14.7±2.5‰). However, as δ 15 N of human and animal waste overlaps, analysis of boron isotopes (δ 11 B) is used to distinguish anthropogenic sources from natural sources. Sampling along the Great Miami River, Mad River, and Stillwater River within the watershed provides insights into contaminant sources contributing to high levels of nitrate. In general, the δ 15 N from river samples collected during low river flow lies within a range of animal manure and human waste, whereas δ 15 N values of groundwater suggest that the nitrates might be derived from soil organic nitrogen and synthetic fertilizers. This research provides a regional baseline for nitrate contaminant source tracing and helps to better inform future studies.
Understanding patterns of Pliocene environmental and climate change using data from terrestrial d... more Understanding patterns of Pliocene environmental and climate change using data from terrestrial deposits helps to identify factors which govern the climate, and to unravel potential links between regional and global climate conditions. We use the stable carbon (C) and oxygen (O) isotopic composition of bioapatite from fossil tooth enamel to reconstruct Pliocene environmental and climatic changes at Dikika and Galili,
• δ 18 O shows seasonality with high values in the summer and low values in the winter. • Precipi... more • δ 18 O shows seasonality with high values in the summer and low values in the winter. • Precipitation isotopic composition is mainly controlled by temperature. • The δ 18 O-T relationship varies seasonally with highest slope in winter. • Dayton gets moisture from Pacific, Gulf of Mexico, Arctic and Continental sources. • δ 18 O from different sources are similar within a season but vary seasonally.
In many cases, there is an irony when regional economic growth is high, but most of the populatio... more In many cases, there is an irony when regional economic growth is high, but most of the population is poor due to the income disparity. The impacts of income disparities on social conflict are the main reasons for doing this research. The panel data regression analysis is used in this research. Therefore, the results show that an increase in income disparity will be followed by a rise in social conflict. Income disparities promote a lower middle group feels unfair and reflect their disappointment in a dysfunctional behavior that deviates from the rules. A group of people who mutually have dysfunctional behavior leads to social conflicts.
A series of major hominin speciation events that took place in East Africa during the Pliocene-Pl... more A series of major hominin speciation events that took place in East Africa during the Pliocene-Pleistocene epochs have been linked to landscape evolution. Previous studies examining the role of climatic and environmental pressures on hominin evolution have used either discontinuous outcrops exposed proximal to, or marine sediments distal from, hominid fossil sites. These sediments have been used to develop stable carbon and oxygen isotope (δ13C, δ18O) proxy-based reconstructions of ancient environments, showing evidence for a series of changes including a transition from woodland to savannah-dominated environments. This work has prompted researchers to hypothesize that speciation events coincided with cooling of the African climate and local aridification during times of glacial intensification. It is speculated that local environmental pressures led to an increase in brain size, breakthroughs in stone technology, and the migration of Homo sapiens out of Africa. However, recent clum...
Much of the Great Miami River Watershed's streams and aquifers in southwestern, Ohio are impacted... more Much of the Great Miami River Watershed's streams and aquifers in southwestern, Ohio are impacted by nitrate contaminants originating from anthropogenic sources. These include synthetic/inorganic fertilizers for agriculture, animal manure, and municipal wastewater. High nitrate concentrations cause ecological disturbances affecting organisms across all trophic levels. Nitrate levels greater than 10 mg/l also pose a danger to human health, if the contaminant reaches drinking water sources. Although networks of water quality monitoring stations in the watershed collect data on nitrate concentrations in surface and groundwater, a nitrate contaminant source has not been identified. In this study we used isotope ratios of nitrogen (δ 15 N) and oxygen (δ 18 O) in nitrates to identify nitrate sources for surface and groundwater. Initially we fingerprinted the isotopic composition of the main nitrate contaminant sources in the watershed. The results show a distinct low δ 15 N for commercial synthetic fertilizers (0.7±4‰) and high δ 15 N for animal and human waste (14.7±2.5‰). However, as δ 15 N of human and animal waste overlaps, analysis of boron isotopes (δ 11 B) is used to distinguish anthropogenic sources from natural sources. Sampling along the Great Miami River, Mad River, and Stillwater River within the watershed provides insights into contaminant sources contributing to high levels of nitrate. In general, the δ 15 N from river samples collected during low river flow lies within a range of animal manure and human waste, whereas δ 15 N values of groundwater suggest that the nitrates might be derived from soil organic nitrogen and synthetic fertilizers. This research provides a regional baseline for nitrate contaminant source tracing and helps to better inform future studies.
Understanding patterns of Pliocene environmental and climate change using data from terrestrial d... more Understanding patterns of Pliocene environmental and climate change using data from terrestrial deposits helps to identify factors which govern the climate, and to unravel potential links between regional and global climate conditions. We use the stable carbon (C) and oxygen (O) isotopic composition of bioapatite from fossil tooth enamel to reconstruct Pliocene environmental and climatic changes at Dikika and Galili,
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Papers by Zelalem Bedaso