Feedbacks Among Climate, Soils, Vegetation, and Erosion Drive Valley Asymmetry Development in the Mountains of Central Idaho

Aspect has long been recognized as a significant source of landscape variability, which is induced by the orientation of land surfaces relative to solar incidence. Insolation differences on opposing aspects (e.g., north and south-facing slopes) act as localized climatic perturbations, altering surface energy balances and temperatures. Over shorter timescales, aspect-induced changes to the energy balance alter snow pack dynamics, soil water input rates and seasonality, and plant available water and water stress. Over longer timescales, aspect-induced insolation variability affects bedrock weathering rates and depths, soil and regolith development, vegetation type and density, erosion rates and processes, and ultimately hillslope and drainage forms. In turn, differences in landscape evolution on the opposite sides of valleys lead to valley asymmetry development. The primary goals of this work are to 1) summarize available aspect-related hydrologic, ecologic and pedologic data for the Dry Creek Experimental Watershed (DCEW), fill knowledge gaps by investigating aspect-related differences in geomorphic characteristics and processes, and develop an integrative conceptual framework for how landscapes respond to aspect-induced insolation variability and how valley asymmetry develops. In particular, we assess 1) how aspect drives differences in fire and erosion rates, 2) how critical zone characteristics vary with aspect and how aspect-sensitivity changes with elevation, and 3) how aspect-related differences in critical zone response alter runoff production, drainage incision, and catchment competition, which drive valley asymmetry development. Surprisingly, erosion rates for north and south-facing catchments do not appear to have varied significantly during the Holocene, despite dramatic differences in landscape characteristics (e.g., vegetation cover, soils, hydrologic processes, and landforms). This suggests that the valley asymmetry has not been actively developing, and is a relict feature of either initial landscape response to aspect, or specific climate intervals (e.g., glacial periods). Erosion rates for the margin of the Idaho batholith are lower than those in the interior batholith, reflecting lower rates of incision. Elevation appears to modify the sensitivity of landscapes to aspect-induced climate perturbation. Critical zone properties appear to be most sensitive to aspect-induced climate perturbation at lower elevations (~1,100 m), and aspect-sensitivity diminishes towards higher elevations (~2,100 m). Changes in precipitation and temperature with increasing elevation appear to alleviate moisture stress, causing aspect-induced insolation and temperature variability to have less of an effect. Reduced landscape sensitivity to aspect at higher elevations explains why previously mapped slope asymmetry diminishes towards these elevations throughout the region. Drainage incision and expansion are more pronounced on south-facing valley sides. South-facing catchments have shallower, coarser soils that yield more runoff per unit drainage area. Changes to the water balance at pedon-scales appear to influence how fluvial process scale with drainage area, which impacts catchment-scale erosive efficiency. Enhanced drainage incision in south-facing catchments, in conjunction with more effective diffusive erosion, appears to have promoted divide migration and land surface elongation. Importantly, land surface degradation and elongation reduce geomorphic gradients, which serve as negative feedbacks by reducing denudation differences between north and south-facing valley sides, and effectively drive valley asymmetry development towards dynamic equilibrium. This suggests that although valley asymmetry clearly reflects differences in past erosion, it may actually develop as a landscape response to counteract aspect-induced differences in erosion. Where valley asymmetry is most pronounced, we suspect there may be little difference in rates of erosion. Valley asymmetry may be a remotely measurable characteristic of landscapes that reflect their proximity to stable states

The Judicial Philosophy of Roger Traynor

Roger Traynor served on the Supreme Court of California for nearly thirty years, including more than five years as Chief Justice of California. He is arguably one of the great judges and legal reformers in the history of the common law. This Article, written by the inaugural Roger Traynor Summer Research Professor at Hastings College of the Law, focuses on Justice Traynor\u27s judicial philosophy as found in twenty-four articles that he wrote between 1956 and 1980. The Article begins with a brief overview of the major developments in American legal process theory, first reviewing traditional views of the judicial process, then focusing on the more modem (meaning twentieth-century) movement away from those traditional views. Justice Traynor\u27s judicial philosophy and its relevance for our time is then examined in detail. This examination reveals Justice Traynor\u27s view of judging as a creative process. The Article highlights the Justice\u27s interpretation and exploration of the factors and limitations that he believed drive the art of creative judging

POTENTIAL CHEMICALS TO MANAGE LlGHT GOOSE POPULATIONS

Over-abundant light geese are having long-term negative effects on the Arctic tundra ecosystem. Significant damage to native plants, increases in soil degradation and impacts on bird communities are likely to be the main consequences (Batt 1998). The extent of which over-abundant light geese reduce food and cover for other wildlife on wintering grounds and migration routes is not well documented, although anecdotal observations suggest that light geese could compete with wintering waterfowl for food, i.e. Louisiana rice fields (J. L. Curnmings, National Wildlife Research Center, personal observation)

Discontinuous Mode Power Supply

A document discusses the changes made to a standard push-pull inverter circuit to avoid saturation effects in the main inverter power supply. Typically, in a standard push-pull arrangement, the unsymmetrical primary excitation causes variations in the volt second integral of each half of the excitation cycle that could lead to the establishment of DC flux density in the magnetic core, which could eventually cause saturation of the main inverter transformer. The relocation of the filter reactor normally placed across the output of the power supply solves this problem. The filter reactor was placed in series with the primary circuit of the main inverter transformer, and is presented as impedance against the sudden changes on the input current. The reactor averaged the input current in the primary circuit, avoiding saturation of the main inverter transformer. Since the implementation of the described change, the above problem has not reoccurred, and failures in the main power transistors have been avoided