Efficient Forest Data Structure for Evolutionary Algorithms Applied to Network Design

The design of a network is a solution to several engineering and science problems. Several network design problems are known to be NP-hard, and population-based metaheuristics like evolutionary algorithms (EAs) have been largely investigated for such problems. Such optimization methods simultaneously generate a large number of potential solutions to investigate the search space in breadth and, consequently, to avoid local optima. Obtaining a potential solution usually involves the construction and maintenance of several spanning trees, or more generally, spanning forests. To efficiently explore the search space, special data structures have been developed to provide operations that manipulate a set of spanning trees (population). For a tree with n nodes, the most efficient data structures available in the literature require time O(n) to generate a new spanning tree that modifies an existing one and to store the new solution. We propose a new data structure, called node-depth-degree representation (NDDR), and we demonstrate that using this encoding, generating a new spanning forest requires average time O(root n). Experiments with an EA based on NDDR applied to large-scale instances of the degree-constrained minimum spanning tree problem have shown that the implementation adds small constants and lower order terms to the theoretical bound.

A hymenopterists' guide to the Hymenoptera Anatomy Ontology: utility, clarification, and future directions

Hymenoptera exhibit an incredible diversity of phenotypes, the result of similar to 240 million years of evolution and the primary subject of more than 250 years of research. Here we describe the history, development, and utility of the Hymenoptera Anatomy Ontology (HAO) and its associated applications. These resources are designed to facilitate accessible and extensible research on hymenopteran phenotypes. Outreach with the hymenopterist community is of utmost importance to the HAO project, and this paper is a direct response to questions that arose from project workshops. In a concerted attempt to surmount barriers of understanding, especially regarding the format, utility, and development of the HAO, we discuss the roles of homology, "preferred terms", and "structural equivalency". We also outline the use of Universal Resource Identifiers (URIs) and posit that they are a key element necessary for increasing the objectivity and repeatability of science that references hymenopteran anatomy. Pragmatically, we detail a mechanism (the "URI table") by which authors can use URIs to link their published text to the HAO, and we describe an associated tool (the "Analyzer") to derive these tables. These tools, and others, are available through the HAO Portal website (http://portal.hymao.org). We conclude by discussing the future of the HAO with respect to digital publication, cross-taxon ontology alignment, the advent of semantic phenotypes, and community-based curation.

Ammonia losses estimated by an open collector from urea applied to sugarcane straw

The quantification of ammonia (NH3) losses from sugarcane straw fertilized with urea can be performed with collectors that recover the NH3 in acid-treated absorbers. Thus, the use of an open NH3 collector with a polytetrafluoroethylene (PTFE)-wrapped absorber is an interesting option since its cost is low, handling easy and microclimatic conditions irrelevant. The aim of this study was to evaluate the efficiency of an open collector for quantifying NH3-N volatilized from urea applied over the sugarcane straw. The experiment was carried out in a sugarcane field located near Piracicaba, São Paulo, Brazil. The NH3-N losses were estimated using a semi-open static collector calibrated with 15N (reference method) and an open collector with an absorber wrapped in PTFE film. Urea was applied to the soil surface in treatments corresponding to rates of 50, 100, 150 and 200 kg ha-1 N. Applying urea-N fertilizer on sugarcane straw resulted in losses NH3-N up to 24 % of the applied rate. The amount of volatile NH3-N measured in the open and the semi-open static collector did not differ. The effectiveness of the collection system varied non-linearly, with an average value of 58.4 % for the range of 100 to 200 kg ha-1 of urea-N. The open collector showed significant potential for use; however, further research is needed to verify the suitability of the proposed method.

“You Can't Always Get What You Want” : A Novel Research Paradigm to Explore the Relationship between Multiple Intentions and Behaviours

Funded by •Centre for Translational Research in Public Health •United Kingdom Clinical Research Collaboration Public Health Research Centre •British Heart Foundation •Cancer Research United Kingdom •Economic and Social Research Council •Medical Research Council •National Institute for Health

Hazardous wastes : a risk-benefit framework applied to cadmium and asbestos /

SRI project no. EGU-3561 ; EPA contract no. 68-01-2915

How basic research reaps unexpected rewards /

Mode of access: Internet.

Information, perception and regional policy /

Mode of access: Internet.

Science and engineering state profiles : Fall 1996 : detailed statistical tables /

"NSF 97-306."

Automation technology applied to public service : proceedings of a Conference on Automation Technology Applied to Public Service, held at the National Bureau of Standards, Gaithersburg, Maryland, May 21-22, 1974 /

Mode of access: Internet.

The science and technology resources of Japan : a comparison with the United States

Mode of access: Internet.

Trends and opportunities in materials research /

"NSF 84-17"--p. [4] of cover.

Small business guide to federal R&D funding opportunities /

"March 1986."

Individuals and families in transition : understanding change through longitudinal data : papers presented at the Social Science Research Council conference in Annapolis, Maryland, March 16-18, 1988 /

Mode of access: Internet.

A partial list of the publications of the National Research Council to January 1, 1922.

"Revised and reprinted from the Proceedings of the National Academy of Sciences [vol.] 7, 1921, pages 351-362."

Irrigation & drainage : a national research plan to meet competing demands and protect the environment.

Shipping list no.: 2002-0055-P.