Quantifying Geomorphic Controls on Time in Weathering Systems

AbstractThe time minerals spend in the weathering zone is crucial in determining soil biogeochemical cycles, solid state chemistry and soil texture. This length of time is closely related to erosion rates and can be modulated by sediment transport, mixing rates within the soil and the temporal evolution of erosion. Here we describe how time length can be approximated using geomorphic metrics and how topography reveals changing residence times of minerals within soils. We also show model simulations from a field site in California that can reproduce observed solid state geochemistry in the eroding portion of the landscape

Establishing the validity of the Personality Assessment Inventory drug and alcohol scales in a corrections sample

Abstract Although not originally designed for implementation in correctional settings, researchers and clinicians have begun to use the Personality Assessment Inventory (PAI) to assess offenders. A relatively small number of studies have made attempts to validate the alcohol and drug abuse scales of the PAI, and only a very few studies have validated those scales in nonclinical correctional samples. The current study examined evidence of convergent and discriminant validity for the substance abuse scales on the PAI in a large, nonclinical sample of offenders. The net sample for the current study consisted of 1,120 federal inmates. Both the drug abuse and alcohol scales showed good convergent validity through high correlations with relevant proximal and distal indicators of substance use across multiple measures from several data sources. Discriminant validity was established as neither scale showed any "erroneous" correlations after controlling for the other scale. Implications for future research and practice are discussed

Impact of change in erosion rate and landscape steepness on hillslope and fluvial sediments grain size in the Feather River Basin (Sierra Nevada, California)

The characteristics of the sediment transported by rivers (e.g. sediment flux, grain size distribution – GSD) dictate whether rivers aggrade or erode their substrate. They also condition the architecture and properties of sedimentary successions in basins. In this study, we investigate the relationship between landscape steepness and the grain size of hillslope and fluvial sediments. The study area is located within the Feather River basin in northern California, and studied basins are underlain exclusively by tonalite lithology. Erosion rates in the study area vary over an order of magnitude, from > 250 mm ka<sub>−1</sub> in the Feather River canyon to < 15 mm ka<sub>−1</sub> on an adjacent low-relief plateau. We find that the coarseness of hillslope sediment increases with increasing hillslope steepness and erosion rates. We hypothesise that, in our soil samples, the measured 10-fold increase in D<sub>50</sub> and doubling of the amount of fragments larger than 1 mm when slope increases from 0.38 to 0.83 m m<sub>−1</sub> is due to a decrease in the residence time of rock fragments, causing particles to be exposed for shorter periods of time to processes that can reduce grain size. For slopes in excess of 0.7 m m<sub>−1</sub> , landslides and scree cones supply much coarser sediment to rivers, with D<sub>50</sub> and D<sub>84</sub> more than one order of magnitude larger than in soils. In the tributary basins of the Feather River, a prominent break in slope developed in response to the rapid incision of the Feather River. Downstream of the break in slope, fluvial sediment grain size increases, due to an increase in flow competence (mostly driven by channel steepening) as well as a change in sediment source and in sediment dynamics: on the plateau upstream of the break in slope, rivers transport easily mobilised fine-grained sediment derived exclusively from soils. Downstream of the break in slope, mass wasting processes supply a wide range of grain sizes that rivers entrain selectively, depending on the competence of their flow. Our results also suggest that, in this study site, hillslopes respond rapidly to an increase in the rate of base-level lowering compared to rivers

Evolution of hillslope soils: The geomorphic theater and the geochemical play

How and how fast do hillslope soils form as the landscape’s morphology changes over time? Here results are shown from an ongoing study that simultaneously examines the morphologic and geochemical evolution of soil mantled hillslopes that have been exposed to distinctively different denudation history. In Northern Sierra Nevada, California, the authors are investigating a tributary basin to the Middle Fork Feather River. A major incision signal from the river is well marked in a knickpoint within the tributary basin which stretches from its mouth to the Feather River at an elevation of 700 m to the plateau at an elevation of 1500 m. Hillslopes are significantly steeper below the knickpoint. The area’s total denudation rates are currently being constrained using cosmogenic radio nuclides, but a previous study suggested an order of magnitude difference in total denudation rates below and above the knickpoint. When compared with topographic attributes calculated from LIDAR data, physical erosion rates can be modeled as a linear function of ridge top curvature. Surprisingly, over the wide range of total denudation rates, soil thicknesses do not vary significantly until a threshold point where soil mantled landscapes abruptly shift to bedrock dominated landscapes. Bioturbation by tree falls appear to buffer soil thickness over the wide range of physical soil erosion rates. From three hillslopes with different physical erosion rates, the concentrations of Zr, which were considered conserved during dissolution and leaching, were determined and used as a proxy for the degree of mass losses via chemical denudation. There is a general trend that colluvial soils along the hillslopes with lower physical erosion rates are enriched in fine size fractions, Zr, and pedogenic crystalline Fe oxides. Likewise, the saprolites show greater degrees of chemical denudation at the sites above the knickpoint, presumably because of the saprolites’ longer turnover time in the slowly eroding landscapes. In the two steep hillslopes below the knickpoint, no significant or systematic topgraphic trends were found for soil geochemistry. However, soils show increasing Zr enrichment in the downslope direction in the hillslope above the knickpoint, which suggests a critical denudation rate beyond which soils’ turnover time is too short to develop a geochemical catena. As detailed CRN-based soil production rates and catchment scale denudation rates are acquired, the data will be combined with a mass balance model to calculate the rates of chemical denudation and weathering in soils and saprolites along the denudation gradient

Impacts of Student-Led Sustainability Efforts at Fresno State

As California State University, Fresno (Fresno State) continues to develop institutional capacity to improve sustainability within the contexts of the Association for the Advancement of Sustainability in Higher Education (AASHE), the university mission, and strategic objectives identified by the California State University (CSU), student activism has played a critical role in establishing the groundwork for current efforts. Despite progress towards an overarching goal of integrating sustainability into all parts of the institution, near constant turnover within the institution and student-led organizations often leaves uncertainties about institutionalization, with questions often arising about the respective roles of faculty, staff, and students. It is also often unclear whether the sustainability efforts contributed by students acts to empower them or if it serves as an additional burden. In our research, we compare a case-study of our student-led efforts towards the integration of sustainability at Fresno State to a landscape analysis of integrative sustainability efforts findable across websites of all other CSUs. The aim of this paper is to examine the current roles that students are playing in both campus and system-wide sustainability efforts. Case study and landscape analysis results suggest that while students look to their campuses to provide sustainability leadership, youth-led efforts are apparently the most numerous in advancing efforts across the CSU system. This supports more contemporary views of students and the need for asset-mindedness, as well as the idea that educational institutions--who are charged with leading sustainability (i.e., AASHE)--can increase equity and reduce student burdens by recognizing, supporting, and intentionally collaborating with leading student efforts

Retardation of arsenic transport through a Pleistocene aquifer

Groundwater drawn daily from shallow alluvial sands by millions of wells over large areas of south and southeast Asia exposes an estimated population of over a hundred million people to toxic levels of arsenic. Holocene aquifers are the source of widespread arsenic poisoning across the region. In contrast, Pleistocene sands deposited in this region more than 12,000 years ago mostly do not host groundwater with high levels of arsenic. Pleistocene aquifers are increasingly used as a safe source of drinking water and it is therefore important to understand under what conditions low levels of arsenic can be maintained. Here we reconstruct the initial phase of contamination of a Pleistocene aquifer near Hanoi, Vietnam. We demonstrate that changes in groundwater flow conditions and the redox state of the aquifer sands induced by groundwater pumping caused the lateral intrusion of arsenic contamination more than 120 metres from a Holocene aquifer into a previously uncontaminated Pleistocene aquifer. We also find that arsenic adsorbs onto the aquifer sands and that there is a 16–20-fold retardation in the extent of the contamination relative to the reconstructed lateral movement of groundwater over the same period. Our findings suggest that arsenic contamination of Pleistocene aquifers in south and southeast Asia as a consequence of increasing levels of groundwater pumping may have been delayed by the retardation of arsenic transport

Retardation of arsenic transport through a Pleistocene aquifer

Groundwater drawn daily from shallow alluvial sands by millions of wells over large areas of south and southeast Asia exposes an estimated population of over a hundred million people to toxic levels of arsenic1. Holocene aquifers are the source of widespread arsenic poisoning across the region2, 3. In contrast, Pleistocene sands deposited in this region more than 12,000 years ago mostly do not host groundwater with high levels of arsenic. Pleistocene aquifers are increasingly used as a safe source of drinking water4 and it is therefore important to understand under what conditions low levels of arsenic can be maintained. Here we reconstruct the initial phase of contamination of a Pleistocene aquifer near Hanoi, Vietnam. We demonstrate that changes in groundwater flow conditions and the redox state of the aquifer sands induced by groundwater pumping caused the lateral intrusion of arsenic contamination more than 120 metres from a Holocene aquifer into a previously uncontaminated Pleistocene aquifer. We also find that arsenic adsorbs onto the aquifer sands and that there is a 16–20-fold retardation in the extent of the contamination relative to the reconstructed lateral movement of groundwater over the same period. Our findings suggest that arsenic contamination of Pleistocene aquifers in south and southeast Asia as a consequence of increasing levels of groundwater pumping may have been delayed by the retardation of arsenic transport.National Science Foundation (U.S.) (NSF grant EAR09-11557)Swiss Agency for Development and Cooperation (Grant NAFOSTED 105-09-59-09 to CETASD, the Centre for Environmental Technology and Sustainable Development (Vietnam))National Institute of Environmental Health Sciences (NIEHS grant P42 ES010349)National Institute of Environmental Health Sciences (NIEHS grant P42 ES016454

A social history of the alternative press in Kansas, 1875-1922

Typescript (photocopy).Digitized by Kansas Correctional Industrie

Mid-American Review of Sociology, Volume 5, Number 2 (WINTER, 1980): Book Review

Review of Barbara Sherman HeyI's "The Madam as Entrepreneur: Career Management in House Prostitution