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While manmade slopes are traditionally constructed with planar cross-sections, natural stable slopes are usually curvilinear with significant concavity of the profile. This concavity occurs as a result of evolutionary processes in which rain-driven erosion and sediment transport are balanced through slope shape adjustments. At the point of equilibrium, a relatively steady concavity with a uniform erosion rate is observed over time. Nevertheless, a true equilibrium state is possible only if mechanical stability is satisfied. In this study, concave profiles in rainfall erosion equilibrium were found based on the principles of the well-known RUSLE2 model. Results showed the existence of a family of steady shapes satisfying the condition of uniform normalized erosion rate. Those steady concave shapes that also satisfied long-term mechanical stability were then investigated. The overall results suggest that concave slopes can be constructed to achieve both minimal steady-state erosion equilibrium and mechanical stability, leading to more natural and sustainable landforms with minimal sediment delivery during initial slope adjustments. [ABSTRACT FROM AUTHOR]

The Revised Universal Soil Loss Equation, Version 2 (RUSLE2), provides robust estimates of average annual sheet and rill erosion for one-dimensional hillslope representations. Extensive databases describing climate, soils, and management options have been devel-oped and are widely used in the United States for conservation planning. Recent RUSLE2 enhancements allow estimation of erosion and runoff from a representative sequence of run-off events that are suitable for linkage with an ephemeral gully model. This paper reviews the sensitivity of RUSLE2 erosion estimates to possible climate change scenarios, demonstrates its ability to evaluate alternative management adaptations, and compares predictions with observations of runoff and sediment yield from a 6.6 ha (16 ac) research watershed located near Treynor, Iowa. When applied to a representative hillslope profile with conventional tillage corn (Zea mays L.), increasing monthly temperature by 0.8°C (1.5°F) and rainfall depth, rain-fall erosivity density, and 10-year, 24-hour rainfall depth each by 10% cumulatively increased sheet and rill erosion by 47% and increased runoff by 33%, assuming there was no change in corn yield. If the climate changes decreased corn yield by 10%, the overall effect was to increase soil loss for conservation planning by 63%.These results demonstrate that modest and expected changes in climate will significantly increase the risk of soil erosion, and improved conservation management will be an important part of successful adaptation. [ABSTRACT FROM AUTHOR]

Although conservation planning for agricultural lands has evolved to its current relatively stable form over many decades, conservation planning for construction sites is still in its infancy. This project drew on the resources of various agencies and researchers to develop a conservation planning tool specifically geared towards meeting construction site planning needs in Wisconsin, basing it on the Revised Universal Soil Loss Equation, version 2 (RUSLE2). The project began by deconstructing the planning process itself to determine possible approaches and critical elements, and used those pieces to build a rational new approach to construction site conservation planning. Although no changes were required to the erosion or sediment delivery calculations in RUSLE2, this new tool required substantial changes to the database, the interface, and how the results were presented and packaged. The lessons learned in this effort should be instructive to both a general discussion of the construction site planning process and to attempts to develop other tools that meet this need. [ABSTRACT FROM AUTHOR]

We studied microbial communities in the water column during the fall 2002 Chinook salmon (Oncorhynchus tshawytscha) run on the Feather River in northern California. We quantified culturable heterotrophic bacteria, live/dead bacteria, and Aeromonas spp. bacteria in the water column. Concentrations of each group peaked two weeks following the peak of new salmon carcasses in the river then declined. During the fall 2003 Chinook salmon spawning season we used fluorescent in situ hybridization with domain-specific DNA probes to characterize changes in epilithic biofilm communities. Eukarya counts were lower than Bacteria counts earlier in the salmon run; however, by the end of the salmon migration season, cell concentrations of Bacteria and Eukarya were approximately equal. Chlorophyll a concentrations from epilithic biofilm began to increase in parallel with the increase in Eukarya. Since the biofilms persisted through the spawning season, it is possible that these communities support a food chain that leads to insect populations which become nutrients for the newly hatched salmon fry in the winter and spring. [ABSTRACT FROM AUTHOR]

Researchers in the University of Tennessee Begetable Initiative wanted convincing proof that no-till transplanted vegetables and tobacco reduced negative environmental impacts, as has been proven for no-till seeding of other crops. This led to a two-year replicated field plot study on two soils with slopes typical of east Tennessee agriculture, planted in tomatoes or tobacco with either a no-till transplanter or a more standard tillage-based system. The runoff from the plots was collected and analyzed for sediment and nutrient content. In comparison to the tillage-based system, no-till transplanting on average reduced erosion by 92 percent and average total Kjeldahl nitrogen surface movement off of the plots by 83 percent. The no-till transplanting also reduced total phosphorus and total nitrate plus nitrite surface water runoff significantly (at a = 0.05) in two of three comparisons. Results for total runoff showed no significant trend across tillage types, soils, or crops. Finally, phosphate surface water runoff was a very small portion of total phosphorus movement but showed mized results, with significantly higher no-till system values in two of three cases. These results demonstrate that no-till transplanting can substantially reduce the overall environmental impact of specialty crop production in comparison to tillage-based systems. [ABSTRACT FROM AUTHOR]

Soil erosion and depositional processes result in changes in topographic and soil profile properties over time. In spite of this, few current soil erosion models account for these changes. To begin to address this deficiency, a spatially distributed version of RUSLE2 was developed and used in combination with the tillage erosion model TELEM. These models were applied to a 6.6 ha research watershed near Treynor, Iowa, where runoff and sediment yield were measured from 1975 to 2002. The watershed contained a grassed waterway, and~l m wide grass hedges were established in 1991, with 15.4 m intervals between the grass hedges. Beginning in 1996, no-till management replaced conventional tillage management in the watershed. Using a 3 m raster DEM, concentrated flow channels that ended RUSLE2 hills lope profiles were delineated wherever contributing areas exceeded 600 m². Average monthly runoff and sediment delivery to concentrated flow areas were compared with measured monthly runoff and sediment delivery at the watershed outlet. For conventional tillage, monthly runoff patterns reasonably matched observations, but measured watershed sediment yield was lower than RUSLE2-predicted hillslope sediment delivery, suggesting that sediment was deposited in the grassed waterway. Grass hedges reduced sediment yield similarly in the RUSLE2 estimates and the measured watershed sediment yield. Conversion to no-till had a much greater impact in reducing RUSLE2 estimates of hillslope erosion than it did on measured watershed sediment yield, suggesting that ephemeral gully erosion remained an important sediment source in this watershed under no-till conditions. To assess the potential influence of distributed patterns of soil erosion and deposition behind the hedges on future erosion estimates, the terrain elevation was modified by summing estimates of water and tillage erosion and deposition that would be expected from 50 years of conventional tillage. As expected, reduced slope gradients generally reduced future erosion. The lack of consideration of erosion or deposition in concentrated flow channels limited the ability of the modeling scheme to reinforce existing ephemeral gully channels. [ABSTRACT FROM AUTHOR]

Attribution of paintings is a critical problem in art history. This study extends machine learning analysis to surface topography of painted works. A controlled study of positive attribution was designed with paintings produced by a class of art students. The paintings were scanned using a chromatic confocal optical profilometer to produce surface height data. The surface data were divided into virtual patches and used to train an ensemble of convolutional neural networks (CNNs) for attribution. Over a range of square patch sizes from 0.5 to 60 mm, the resulting attribution was found to be 60–96% accurate, and, when comparing regions of different color, was nearly twice as accurate as CNNs using color images of the paintings. Remarkably, short length scales, even as small as a bristle diameter, were the key to reliably distinguishing among artists. These results show promise for real-world attribution, particularly in the case of workshop practice. [ABSTRACT FROM AUTHOR]

Attribution of paintings is a critical problem in art history. This study extends machine learning analysis to surface topography of painted works. A controlled study of positive attribution was designed with paintings produced by a class of art students. The paintings were scanned using a chromatic confocal optical profilometer to produce surface height data. The surface data were divided into virtual patches and used to train an ensemble of convolutional neural networks (CNNs) for attribution. Over a range of square patch sizes from 0.5 to 60 mm, the resulting attribution was found to be 60–96% accurate, and, when comparing regions of different color, was nearly twice as accurate as CNNs using color images of the paintings. Remarkably, short length scales, even as small as a bristle diameter, were the key to reliably distinguishing among artists. These results show promise for real-world attribution, particularly in the case of workshop practice. [ABSTRACT FROM AUTHOR]

Nitridation of HfSiO films improves certain physical and electrical properties—when using gate stack layers—such as their crystallization temperature and their resistance to interdiffusion. We have studied the band alignment of HfSiO and HfSiON films by soft x-ray photoemission, oxygen K-edge x-ray absorption, and spectroscopic ellipsometry. Nitridation of HfSiO reduced the band gap by 1.50 eV±0.05 eV, and the valence- and conduction-band offsets by 1.2 eV±0.1 eV and 0.33 eV±0.05 eV, respectively. Although the band-gap reduction should lead to increased leakage, the barrier heights are still sufficient for proposed near-future complementary metal-oxide-semiconductor applications. [ABSTRACT FROM AUTHOR]