Building Consortia-Based it Solutions: A Decision Support Architecture for Agencies in Multiple State Governments

Consortia-based IT solutions can be found in many industries, but they pose special management challenges. This article describes an example from the public sector in which the outcomes include a decision support architecture that facilitates within-organization and cross-organization data analysis and reporting, as well as a Web-based knowledge management store for participants. the author argues that the governance model, processes, and key success factors from this project can be useful for those embarking on multi-organizational projects in which highly autonomous units have incentives to participate.     

Editor's Introduction

This paper reviews the state of the art in processing and extraction of ocean floor manganese nodules. It briefly reviews the mining sites where the abundant rich nodules occur and also discusses the metal distribution in nodules in view of economical processing and extraction of these metal values.

The paper discloses in a detailed manner the physical and chemical characteristics of nodules, including porosity, surface area, water content and the effect of temperature on crystal structure of major constituents of nodules.

In the extraction aspect of nodules, the paper reviews two different extraction schemes revealed in the literature, namely hydrometallurgical treatment and pyrometallurgical treatment. The hydrometallurgical treatments include acid leaching, ammonia leaching, leaching with reducing agents and leaching after high temperature pre-treatments such as in sulfating rousting, while the pyrometallurgical processes include smelting, chlorination-vaporization and segregation. The paper also covers metal recovery processes from leach liquor.

An economic survey of processing nodules has been made in terms of problems associated with metal-marketing, and impact of metal production from nodules on mineral industries.     

Morphology, optical, and photoelectrochemical properties of electrodeposited nanocrystalline ZnO films sensitized with Cd x Zn1−x S nanoparticles

Nanocrystalline ITO/ZnO films formed by porous zinc oxide microplatelets 1–3 μm in size and 100–200 nm in thickness, which consist of 30–50 nm ZnO crystallites, were sensitized to visible light by Cd _x Zn_1?x S nanocrystals deposited using the method of successive ionic layer adsorption and reaction (SILAR). The composition of Cd _x Zn_1?x S nanocrystals as well as the dependence between molar Cd(II) fraction in the films and the ratio of cadmium and zinc nitrate concentrations in solutions used for the SILAR procedure were determined by a combination of electron, Raman, and energy-dispersive X-ray spectroscopies. The photovoltage observed at illumination of the ITO/ZnO/Cd _x Zn_1?x S heterostructures by white light (λ >400 nm) in aqueous Na₂S solution increases with a decrease of Cd(II) content proportionally to an increment in the conduction band potential of the Cd _x Zn_1?x S nanocrystals. The photocurrent density normalized to the light absorbance of the ITO/ZnO/Cd _x Zn_1?x S films increases by a factor of around four when the conduction band potential of Cd _x Zn_1?x S nanocrystals grows by 220 mV as a result of Cd(II) fraction changing from 1.0 to 0.62–0.67. The results show that Cd _x Zn_1?x S solid solutions are more advantageous sensitizers for the short-wavelength part of the sensitivity window of the liquid-junction solar cells (400–450 nm) than conventionally used cadmium sulfide.     

Microstructure characterization of CVI-densified carbon/carbon composites with various fiber distributions

Mechanical behavior of multi-phase composites is crucially influenced by volume fractions, orientation distributions and geometries of microconstituents. In the case of carbon–carbon composites manufactured by chemical vapor infiltration, the microconstituents are carbon fibers, pyrolytic carbon matrix, and pores. The local variable thickness of the pyrolytic carbon coating, distribution of the fibers and porosity are the main factors influencing the properties of these materials. Two types of fiber arrangements are considered in this paper: 2D laminated preform and random felt. The materials are characterized by determining their densities and their fiber distribution functions, by establishing types of pyrolytic carbon matrix present in the composites, and by studying the porosity. A technique utilizing X-ray computed tomography for estimation of the orientation distribution of the fibers and pores with arbitrary shapes is developed. A methodology based on the processing of microstructure images with subsequent numerical simulation of the coating growth around the fibers is proposed for estimation of the local thickness of the coating. The obtained information is appropriate for micromechanical modeling and prediction of the overall thermo-mechanical properties of the studied composites.     

Proteomic Biomarkers of the Apnea Hypopnea Index and Obstructive Sleep Apnea: Insights into the Pathophysiology of Presence,Severity, and Treatment Response

Obstructive sleep apnea (OSA), a disease associated with excessive sleepiness and increased cardiovascular risk, affects an estimated 1 billion people worldwide. The present study examined proteomic biomarkers indicative of presence, severity, and treatment response in OSA. Participants (n = 1391) of the Stanford Technology Analytics and Genomics in Sleep study had blood collected and completed an overnight polysomnography for scoring the apnea–hypopnea index (AHI). A highly multiplexed aptamer-based array (SomaScan) was used to quantify 5000 proteins in all plasma samples. Two separate intervention-based cohorts with sleep apnea (n = 41) provided samples pre- and post-continuous/positive airway pressure (CPAP/PAP). Multivariate analyses identified 84 proteins (47 positively, 37 negatively) associated with AHI after correction for multiple testing. Of the top 15 features from a machine learning classifier for AHI ≥ 15 vs. AHI < 15 (Area Under the Curve (AUC) = 0.74), 8 were significant markers of both AHI and OSA from multivariate analyses. Exploration of pre- and post-intervention analysis identified 5 of the 84 proteins to be significantly decreased following CPAP/PAP treatment, with pathways involving endothelial function, blood coagulation, and inflammatory response. The present study identified PAI-1, tPA, and sE-Selectin as key biomarkers and suggests that endothelial dysfunction and increased coagulopathy are important consequences of OSA, which may explain the association with cardiovascular disease and stroke.     

Back and forth between continuous and discrete for the working computer scientist

This paper gives a perfect, ideal, discretization of continuous notions. This is a very convenient frame to treat continuous problems or theories with the help of a computer. This is illustrated by the conversion of algorithms using real numbers into algorithms using integers only and the founding of discrete geometry.     

Stability of a hierarchical clustering

Clustering algorithms have the annoying habit of finding clusters even when the data are generated randomly. Verifying that potential clusterings are real in some objective sense is receiving more attention as the number of new clustering algorithms and their applications grow. We consider one aspect of this question and study the stability of a hierarchical structure with a variation on a measure of stability proposed in the literature.^(1,2)Our measure of stability is appropriate for proximity matrices whose entries are on an ordinal scale. We randomly split the data set, cluster the two halves, and compare the two hierarchical clusterings with the clustering achieved on the entire data set. Two stability statistics, based on the Goodman-Kruskal rank correlation coefficient, are defined. The distributions of these statistics are estimated with Monte Carlo techniques for two clustering methods (single-link and complete-link) and under two conditions (randomly selected proximity matrices and proximity matrices with good hierarchical structure). The stability measures are applied to some real data sets.     

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