156,463 research outputs found

    Intelligent interaction in diagnostic expert systems

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    AbstractAdvisory systems help to improve quality in manufacturing. Such systems, however, both human and computerized, are less than perfect and frequently not welcome. Sharp separation between working and learning modes is the main reason for the apparent hostility of advisory systems. Intelligent interaction deploys computerized advisory capabilities by merging working and learning modes. We have developed a knowledge-based interactive graphic interface to a circuit pack diagnostic expert system. The graphic interface integrates both the domain knowledge (i.e. circuit pack) and the troubleshooting knowledge (i.e. diagnostic trees). Our interface dynamically changes the amount of detail presented to the user as well as the input choices that the user is allowed to make. These changes are made using knowledge-based models of the user and of the circuit pack troubleshooting domain. The resulting system, McR, instead of guiding the user by querying for input, monitors users actions, analyzes them and offers help when needed. McR is able both to advise “how-to-do-it” by reifying shallow knowledge from the deep knowledge, and to explain intelligently “how-does-it-work” by abstracting deep knowledge from the hallow knowledge, McR is used in conjunction with the STAREX expert sytem which is installed at AT&T factory

    Budburst Protocol

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    The purpose of this resource is to observe budburst on selected trees at a Land Cover or Phenology Site. All students will learn about hummingbird natural history and ecology. Students will learn how to identify and age male and female Ruby-throated Hummingbirds and to observe migration and feeding behavior. Students will learn how to make connections among hummingbird behavior and weather, climate, food availability, seasonality, photoperiod (day length), and other environmental factors. Educational levels: Primary elementary, Intermediate elementary, Middle school, High school

    The Origin, Succession, and Predicted Metabolism of Bacterial Communities Associated with Leaf Decomposition.

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    Intraspecific variation in plant nutrient and defensive traits can regulate ecosystem-level processes, such as decomposition and transformation of plant carbon and nutrients. Understanding the regulatory mechanisms of ecosystem functions at local scales may facilitate predictions of the resistance and resilience of these functions to change. We evaluated how riverine bacterial community assembly and predicted gene content corresponded to decomposition rates of green leaf inputs from red alder trees into rivers of Washington State, USA. Previously, we documented accelerated decomposition rates for leaves originating from trees growing adjacent to the site of decomposition versus more distant locales, suggesting that microbes have a "home-field advantage" in decomposing local leaves. Here, we identified repeatable stages of bacterial succession, each defined by dominant taxa with predicted gene content associated with metabolic pathways relevant to the leaf characteristics and course of decomposition. "Home" leaves contained bacterial communities with distinct functional capacities to degrade aromatic compounds. Given known spatial variation of alder aromatics, this finding helps explain locally accelerated decomposition. Bacterial decomposer communities adjust to intraspecific variation in leaves at spatial scales of less than a kilometer, providing a mechanism for rapid response to changes in resources such as range shifts among plant genotypes. Such rapid responses among bacterial communities in turn may maintain high rates of carbon and nutrient cycling through aquatic ecosystems.IMPORTANCE Community ecologists have traditionally treated individuals within a species as uniform, with individual-level biodiversity rarely considered as a regulator of community and ecosystem function. In our study system, we have documented clear evidence of within-species variation causing local ecosystem adaptation to fluxes across ecosystem boundaries. In this striking pattern of a "home-field advantage," leaves from individual trees tend to decompose most rapidly when immediately adjacent to their parent tree. Here, we merge community ecology experiments with microbiome approaches to describe how bacterial communities adjust to within-species variation in leaves over spatial scales of less than a kilometer. The results show that bacterial community compositional changes facilitate rapid ecosystem responses to environmental change, effectively maintaining high rates of carbon and nutrient cycling through ecosystems

    Packing spanning graphs from separable families

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    Let G\mathcal G be a separable family of graphs. Then for all positive constants ϵ\epsilon and Δ\Delta and for every sufficiently large integer nn, every sequence G1,,GtGG_1,\dotsc,G_t\in\mathcal G of graphs of order nn and maximum degree at most Δ\Delta such that e(G1)++e(Gt)(1ϵ)(n2)e(G_1)+\dotsb+e(G_t) \leq (1-\epsilon)\binom{n}{2} packs into KnK_n. This improves results of B\"ottcher, Hladk\'y, Piguet, and Taraz when G\mathcal G is the class of trees and of Messuti, R\"odl, and Schacht in the case of a general separable family. The result also implies approximate versions of the Oberwolfach problem and of the Tree Packing Conjecture of Gy\'arf\'as (1976) for the case that all trees have maximum degree at most Δ\Delta. The proof uses the local resilience of random graphs and a special multi-stage packing procedure

    What next? Rewilding as a radical future for the British countryside

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    Rewilding is an optimistic environmental agenda to reverse the loss of biodiversity and reconnect society with nature. This chapter explores Britain’s ecological history, back to the Last Interglacial before the arrival of modern humans, when the climate was similar to today, to analyse how conservationists can learn from the past to rewild the ecosystems of the present and prepare for an uncertain future. Because there is no single point in history that should or could be recreated, rewilding focuses on re-establishing naturally dynamic ecological processes that, through an appropriate sequence of species reintroductions, attempts to move the ecosystem towards a more appropriately biodiverse and functional state. A state that is self-sustaining in the present climate, and that projected for the near future. Specifically, this chapter explores a rewilding solution to conservation challenges associated with over-grazing, limited germination niche availability, and river dynamics: the reintroduction of wolves, wild boar, and beaver respectively. This sequence of reintroductions is suggested to be complimentary, each altering ecosystem dynamics to facilitate the return of the next. Evidence indicates wolves will reduce deer abundance and re-distribute browsing intensity promoting tree regeneration, particularly in riparian areas, increasing woodland availability to the more habitat-dependent wild boar and beaver. An important message behind rewilding is that a rich biodiversity with all guilds well represented, including the ones that polarize public opinion, such as large predators, are important components of ecosystem service rich and self-sustaining ecosystems, particularly in core areas
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