18,048 research outputs found

    The pagenumber of k-trees is O(k)

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    AbstractA k-tree is a graph defined inductively in the following way: the complete graph Kk is a k-tree, and if G is a k-tree, then the graph resulting from adding a new vertex adjacent to k vertices inducing a Kk in G is also a k-tree. This paper examines the book-embedding problem for k-trees. A book embedding of a graph maps the vertices onto a line along the spine of the book and assigns the edges to pages of the book such that no two edges on the same page cross. The pagenumber of a graph is the minimum number of pages in a valid book embedding. In this paper, it is proven that the pagenumber of a k-tree is at most k+1. Furthermore, it is shown that there exist k-trees that require k pages. The upper bound leads to bounds on the pagenumber of a variety of classes of graphs for which no bounds were previously known

    The Evolution of Modern North Carolina Environmental and Conservation Policy Legislation

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    This essay ... will trace the evolution and legislative history of modern environmental policy declarations and their interaction with earlier conservation policy declarations. It will also examine two topics that illustrate the evolution of environmental policy through legislation on subjects that are important elements of environmental law: interbasin transfers of water and intergovernmental pollution control law (the Hardison Amendments ). These two topics were selected to illustrate policy developments reflected in the legislation itself rather than in policy declarations because each of them has had significant legal and political consequences

    The Evolution of Modern North Carolina Environmental and Conservation Policy Legislation

    Get PDF
    This essay ... will trace the evolution and legislative history of modern environmental policy declarations and their interaction with earlier conservation policy declarations. It will also examine two topics that illustrate the evolution of environmental policy through legislation on subjects that are important elements of environmental law: interbasin transfers of water and intergovernmental pollution control law (the Hardison Amendments ). These two topics were selected to illustrate policy developments reflected in the legislation itself rather than in policy declarations because each of them has had significant legal and political consequences

    Weight loss, glycemic control, and cardiovascular disease risk factors in response to differential diet composition in a weight loss program in type 2 diabetes: a randomized controlled trial.

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    ObjectiveTo test whether a weight loss program promotes greater weight loss, glycemic control, and improved cardiovascular disease risk factors compared with control conditions and whether there is a differential response to higher versus lower carbohydrate intake.Research design and methodsThis randomized controlled trial at two university medical centers enrolled 227 overweight or obese adults with type 2 diabetes and assigned them to parallel in-person diet and exercise counseling, with prepackaged foods in a planned menu during the initial phase, or to usual care (UC; two weight loss counseling sessions and monthly contacts).ResultsRelative weight loss was 7.4% (95% CI 5.7-9.2%), 9.0% (7.1-10.9%), and 2.5% (1.3-3.8%) for the lower fat, lower carbohydrate, and UC groups (P < 0.001 intervention effect). Glycemic control markers and triglyceride levels were lower in the intervention groups compared with UC group at 1 year (fasting glucose 141 [95% CI 133-149] vs. 159 [144-174] mg/dL, P = 0.023; hemoglobin A1c 6.9% [6.6-7.1%] vs. 7.5% [7.1-7.9%] or 52 [49-54] vs. 58 [54-63] mmol/mol, P = 0.001; triglycerides 148 [134-163] vs. 204 [173-234] mg/dL, P < 0.001). The lower versus higher carbohydrate groups maintained lower hemoglobin A1c (6.6% [95% CI 6.3-6.8%] vs. 7.2% [6.8-7.5%] or 49 [45-51] vs. 55 [51-58] mmol/mol) at 1 year (P = 0.008).ConclusionsThe weight loss program resulted in greater weight loss and improved glycemic control in type 2 diabetes

    Molecular transport junctions: Current from electronic excitations in the leads

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    Using a model comprising a 2-level bridge connecting free electron reservoirs we show that coupling of a molecular bridge to electron-hole excitations in the leads can markedly effect the source-drain current through a molecular junction.In some cases, e.g. molecules that exhibit strong charge transfer transitions, the contribution from electron-hole excitations can exceed the Landauer elastic current and dominate the observed conduction.Comment: 4 pages, 2 figures, submitted to PR

    Fabrication of bismuth nanowires with a silver nanocrystal shadowmask

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    We fabricated bismuth (Bi) nanowires with low energy electron beam lithography using silver (Ag) nanocrystal shadowmasks and a subsequent chlorine reactive ion etching. Submicron-size metal contacts on the single Bi nanowire were successfully prepared by in situ focused ion beam metal deposition for transport measurements. The temperature dependent resistance measurements on the 50 nm wide Bi nanowires showed that the resistance increased with decreasing temperature, which is characteristic of semiconductors and insulators
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