Quantity,controls and functions of large woody debris in Midwestern USA streams

Large woody debris (LWD) can increase stream habitat heterogeneity by providing structure, altering flow patterns, enhancing sediment deposition, forming pools and retaining organic matter. In North America, the role of LWD has been studied extensively in streams of mature forests (e.g. Pacific Northwest), but few studies have assessed LWD in streams of younger forests (e.g. Midwestern USA). Our objectives were to: (1) quantify the volume and abundance of LWD in a set of Midwestern streams; (2) evaluate possible factors influencing LWD quantity; (3) identify the functional roles of LWD; and (4) compare LWD levels in the upper Midwest to those elsewhere in North America. In 2002 and 2003, we measured LWD and geomorphological variables in 15 low‐gradient streams draining previously logged watersheds in the Upper Peninsula of Michigan. Mean (±SE) LWD volume (0.77 ± 0.12 m³ 100 m⁻²) and abundance (33 ± 3 pieces 100 m⁻¹) were 71% and 10% lesser, respectively, than in streams of similar gradient elsewhere in North America. Channel shape (width:depth ratio) explained 30% of the variation in LWD volume (multiple stepwise regression, P = 0.015) while LWD length and length:channel width combined, explained 72% of the variation in LWD density (multiple stepwise regression, P < 0.0001). About 50% of the LWD either stored sediment or stabilized banks and 14% of the LWD formed pools, although pool density was not significantly related to LWD volume or density. LWD levels, overall, were low in upper Midwestern streams, but the relative importance of that LWD to ecosystem function may be magnified in these wood‐poor systems. Copyright © 2006 John Wiley & Sons, Ltd.     

抽油杆减震器的现场应用情况及效果分析

本文从应用抽油杆减震器前后上下栽荷的变化、不对称循环应力的变化、上下电流系统效率的变化情况、功图图形的变化等方面、分析抽油杆减震器在现场的应用情况.现场应用的19口井,在未使用抽油杆减震器之前平均每年作业1.5井次(包括返工),2004年这19口井共作业23井次,现场鉴定情况19井次为杆断,自2004年4月使用抽油杆减震器后,只有2口井检泵作业,鉴定结果杆断1口,脱节器爪断1口,年少检泵21井次,节省作业费用42万元,同时避免因泵况异常导致的产量损失420吨,每吨原油按1200元计算,获经济效益50.4万元,这19口井全年获经济效益134.4万元.     

Accounting for the ecosystem services of migratory species: Quantifying migration support and spatial subsidies

Migratory species support ecosystem process and function in multiple areas, establishing ecological linkages between their different habitats. As they travel, migratory species also provide ecosystem services to people in many different locations. Previous research suggests there may be spatial mismatches between locations where humans use services and the ecosystems that produce them. This occurs with migratory species, between the areas that most support the species' population viability - and hence their long-term ability to provide services - and the locations where species provide the most ecosystem services. This paper presents a conceptual framework for estimating how much a particular location supports the provision of ecosystem services in other locations, and for estimating the extent to which local benefits are dependent upon other locations. We also describe a method for estimating the net payment, or subsidy, owed by or to a location that balances benefits received and support provided by locations throughout the migratory range of multiple species. The ability to quantify these spatial subsidies could provide a foundation for the establishment of markets that incentivize cross-jurisdictional cooperative management of migratory species. It could also provide a mechanism for resolving conflicts over the sustainable and equitable allocation of exploited migratory species.     

Ammonia oxidizing bacterial community composition and process performance in wastewater treatment plants under low temperature conditions

Nitrification can be difficult to maintain at wastewater treatment plants (WWTPs) during cold periods resulting in disrupted nitrogen removal. The aim of this study was to relate nitrification process performance to abundance and composition of the ammonia oxidizer communities in two closely located municipal WWTPs in Sweden during an eight month period covering seasonal changes and low temperature conditions. Both facilities showed lower NH(4)(+)-N removal efficiency and nitrification rates as temperature decreased. However, one of the plants had a more stable nitrification rate and higher ammonia removal efficiency throughout the entire period. The differences in performance was related to a shift in the composition of the bacterial ammonia oxidizing community from a Nitrosomonas oligotropha-dominated community to a mixed community including also Nitrosomonas ureae-like ammonia oxidizers. This was likely a response to differences in NH(4)(+)-N and organic loading.     

The Interaction of Global Value Chains and Rural Livelihoods: The Case of Smallholder Raspberry Growers in Chile

This paper integrates aspects of global value chain and sustainable rural livelihoods analyses in an exploration of the local impacts of agri‐food globalization in Chile. In particular, it examines the evolution of the raspberry export sector in the context of Chile's non‐traditional agricultural export boom, and considers its importance to smallholder growers and rural households in central Chile. The paper first outlines the geography and structural configuration of the global value chain for Chilean raspberries, and considers modes of governance and forms of coordination between key actors within the chain. Second, the terms and implications of smallholder grower participation in the value chain are explored in a discussion of access to key livelihoods assets. The paper concludes that institutional support to smallholders, even in the case of a crop that is widely seen to have a small‐scale ‘size bias’, remains integral to their capacity to comply with required safety and quality standards and gain and retain market access via the value chain.     

All's not fair in pricing: An initial look at the dual entitlement principle

A new theory in economics (Kahneman, Knetsch, and Thaler, 1986a, b) contends that consumer judgments of seller fairness can explain why sellers in many industries do not raise prices to ration off excess demand. In a small study focusing on automated teller machines (ATM) fees, we obtain empirical support for KKT's prediction that unjustified price increases are perceived as unfair, while cost justification legitimates a price increase in consumers' eyes. We also find, however, that fairness perceptions are not significantly related to behavioral intentions (as the theory would suggest). Many respondents felt the fee was unfair but would not switch banks because of switching costs, while others felt the fee was fair but would switch banks because of the cumulative cost. Research directions are discussed.     

Cost comparisons of reduced-impact and conventional logging in the tropics

Comparisons of the costs of reduced-impact (RIL) and conventional logging (CL) based on new data from Gabon and 10 previously published studies revealed that some tropical forest operators should adopt RIL out of financial self-interest but many may require other motivation. Among the comparisons in which costs were expressed per cubic meter of harvested timber, three reported lower costs for RIL, one showed identical costs with CL, and six reported RIL to be more costly.     

LINKING RIVER MANAGEMENT TO SPECIES CONSERVATION USING DYNAMIC LANDSCAPE‐SCALE MODELS

Efforts to conserve stream and river biota could benefit from tools that allow managers to evaluate landscape‐scale changes in species distributions in response to water management decisions. We present a framework and methods for integrating hydrology, geographic context and metapopulation processes to simulate effects of changes in streamflow on fish occupancy dynamics across a landscape of interconnected stream segments. We illustrate this approach using a 482 km² catchment in the southeastern US supporting 50 or more stream fish species. A spatially distributed, deterministic and physically based hydrologic model is used to simulate daily streamflow for sub‐basins composing the catchment. We use geographic data to characterize stream segments with respect to channel size, confinement, position and connectedness within the stream network. Simulated streamflow dynamics are then applied to model fish metapopulation dynamics in stream segments, using hypothesized effects of streamflow magnitude and variability on population processes, conditioned by channel characteristics. The resulting time series simulate spatially explicit, annual changes in species occurrences or assemblage metrics (e.g. species richness) across the catchment as outcomes of management scenarios. Sensitivity analyses using alternative, plausible links between streamflow components and metapopulation processes, or allowing for alternative modes of fish dispersal, demonstrate large effects of ecological uncertainty on model outcomes and highlight needed research and monitoring. Nonetheless, with uncertainties explicitly acknowledged, dynamic, landscape‐scale simulations may prove useful for quantitatively comparing river management alternatives with respect to species conservation. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.     

Fair markets

The paper challenges a minimalist strategy in business ethics that maintains if it's legal, it's moral. In hard cases, judges decide legal issues by appealing to moral ideals. Investigation shows that the bedrock concept is fairness. Often judges define fairness in terms of non-coerciveness or equality of bargaining power. The prudent manager must look beyond the legal department to the ethical notion of fairness. Moreover, if the courts were to consistently appeal to non-coerciveness and equality of bargaining power, some practices now considered morally acceptable would be neither moral nor legal. Norman E. Bowie is Professor of Philosophy and Director of the Center for the Study of Values at the University of Delaware. He is the author of numerous articles on business ethics and social and political philosophy and of Business Ethics, Making Ethical Decisions (ed.), The Tradition of Philosophy (co-ed.), and Ethical Theory and Business (co-ed.).