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Abstract:The response of rivers and riparian forests to upstream dams shows a regional pattern related to physiographic and climatic factors that influence channel geometry. We carried out a spatial analysis of the response of channel geometry to 35 dams in the Great Plains and Central Lowlands, USA. The principal response of a braided channel to an upstream dam is channel-narrowing, and the principal response of a meandering channel is a reduction in channel migration rate. Prior to water management, braided channels were most common in the southwestern Plains where sand is abundant, whereas meandering channels were most common in the northern and eastern Plains. The dominant response to upstream dams has been channelnarrowing in the southwestern Plains (e.g., six of nine cases in the High Plains) and reduction in migration rate in the north and east (e.g., all of twelve cases in the Missouri Plateau and Western Lake Regions). Channel-narrowing is associated with a burst of establishment of native and exotic woody riparian pioneer species on the former channel bed. In contrast, reduction in channel migration rate is associated with a decrease in reproduction of woody riparian pioneers. Thus, riparian pioneer forests along large rivers in the southwestern Plains have temporarily increased following dam construction while such forests in the north and east have decreased. These patterns explain apparent contradictions in conclusions of studies that ft-mused on single rivers or small regions and provide a framework for predicting effects of dams on large rivers in the Great Plains and elsewhere. These conclusions are valid only for large rivers. A spatial analysis of channel width along 286 streams ranging in mean annual discharge from 0.004 to 1370 cubic meters per second did not produce the same clear regional pattern, in part because the channel geometries of small and large streams are affected differently by a sandy watershed.

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Abstract-With each technology generation, the power delivery network becomes larger and more complicated, making the system analysis process computationally complex. The rising number of on-chip power supplies and intentional decoupling capacitors inserted throughout an integrated circuit further complicates the analysis of the power distribution network. Interactions among the on-chip power supplies, decoupling capacitors, and load circuitry are investigated in this paper. The on-chip power supplies and decoupling capacitors within the power network are simultaneously co-designed and placed. The effect of physical distance on the power supply noise is investigated. This methodology changes conventional practices where the power distribution network is designed first, followed by the placement of the decoupling capacitors.

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