bluuebunny/crossref_metadata_2025_split huggingface dataset:
A knowledge management implementation plan at a leading US technical government organization: a case study
Authors: Liebowitz Jay 
Published: December 2003

AbstractMany organizations are realizing that knowledge management should play an increasing role in achieving the organization's strategic mission. Certainly, as the ‘graying workforce’ ensues (especially in the US Federal Government), knowledge‐sharing activities become evermore paramount as part of the organization's human capital strategy. Unfortunately, many organizations do not have a clear knowledge management implementation plan in mind. To improve this situation, this paper presents a knowledge management implementation plan for a leading US technical government organization. Hopefully, the plan's component parts may be useful to others when considering how to develop a knowledge management implementation plan for themselves. Copyright © 2003 John Wiley & Sons, Ltd.
The aluminum ordering in aluminosilicates: a dipolar 27Al NMR spectroscopy study
Authors: Gee Becky A. 
Published: December 2003

AbstractThe spatial ordering of aluminum atoms in CsAl(SiO3)2 and 3Al2O3·2SiO2 was probed by 27Al dipolar solid‐state NMR spectroscopy. The 27Al response to a Hahn spin‐echo pulse sequence in a series of aluminum‐containing model crystalline compounds demonstrates that quantitative 27Al homonuclear dipolar second moments can be obtained to within ±20% of the theoretical values, if evaluation of the spin‐echo response curve is limited to short evolution periods (2t1 ≤ 0.10 ms). Additionally, selective excitation of the central transition $m = {1 \over 2} \to - {1 \over 2}$ is necessary in order to ensure quantitative results. Restriction of spin exchange affecting the dephasing of the magnetization may decelerate the spin‐echo decay at longer evolution periods. Considering these restraints, the method was used to probe the spatial distribution of aluminum atoms among the tetrahedral sites in two aluminosilicate materials. Experimental 27Al spin‐echo response data for the aluminosilicates CsAl(SiO3)2 (synthetic pollucite) and 3Al2O3·2SiO2 (mullite) are compared with theoretical data based on (I) various degrees of aluminum–oxygen–aluminum bond formation among tetrahedrally coordinated aluminum atoms (Al—O—Al) and (II) the maximum avoidance of Al—O—Al bonding. Analysis of the second moment values and resulting echo decay responses suggests that partial suppression of spin exchange among aluminum atoms in crystallographically distinct sites may contribute to the 27Al spin echo decay in 3Al2O3·2SiO2, thus complicating quantitative analysis of the data. Silicon‐29 and aluminum‐27 magic angle spinning (MAS) NMR spectra of 3Al2O3·2SiO2 are consistent with those previously reported. The experimental 27Al spin‐echo response behavior of CsAl(SiO3)2 differs from the theoretical response behavior based on the maximum avoidance of Al—O—Al bonding between tetrahedral aluminum sites in CsAl(SiO3)2. A single unresolved resonance is observed in both the silicon‐29 and aluminum‐27 MAS spectra of CsAl(SiO3)2. Copyright © 2003 John Wiley & Sons, Ltd.
Orientations of the principal components of electric field gradients and internal motions in dihydrogen ligands from the 2H T1 NMR relaxation data in solution
Authors: Bakhmutov Vladimir I. 
Published: December 2003

AbstractThe deuterium spin–lattice relaxation times in (D2) ligands of W, Ru and Os complexes are reviewed and analyzed in terms of the fast internal (D2) motions: free rotation, librations and 180° jumps. The analysis was performed using quadrupolar coupling constant (DQCC) parameters taken from the solid‐state 2H NMR spectra and density function theory calculations. It is shown that the calculated DQCC values can be corrected for further use in interpretations of deuterium relaxation times for Ru and Os dihydrogen complexes. The resulting data led to a criterion for using the relaxation data to distinguish fast‐spinning dihydrogen ligands. It is shown that the principal components of electric field gradient tensors at D in the dihydrogen ligands are oriented closer to M–D directions Copyright © 2003 John Wiley & Sons, Ltd.
Evidence for spin diffusion in a H,H‐NOESY study of imidazolium tetrafluoroborate ionic liquids
Authors: Heimer Norman E. , Del Sesto Rico E. , Carper W. Robert 
Published: December 2003

AbstractThe ionic liquids 1‐ethyl‐3‐methylimidazolium tetrafluoroborate ([EMIM][BF4]) and 1‐methyl‐3‐propylimidazolium tetrafluoroborate ([PMIM][BF4]) were studied by H,H‐NOESY NMR using a cross‐relaxation matrix analysis. Cross‐peak intensities are seen to increase with increasing mixing time. Experimental and theoretical hydrogen–hydrogen distances are in agreement at short mixing times (50 ms). Mixing times longer than 50 ms result in an increasing contribution of spin diffusion that produces unrealistically short hydrogen–hydrogen distances. Gas‐phase ab initio molecular structures are obtained using Hartree–Fock (HF) and density functional theory (B3LYP) methods at the 6311 + G(2d,p) basis set level. The hydrogen–hydrogen distances obtained from the theoretical structures are in reasonable agreement with those calculated from the cross‐relaxation matrices. Published in 2003 by John Wiley & Sons, Ltd.
Computational study of the chair–chair interconversion and stereoelectronic interactions in 1,2,3‐trithiacyclo‐hexane (1,2,3‐trithiane)
Authors: Freeman Fillmore , Cha Chansa 
Published: December 2003

AbstractAb initio theory, density functional theory (DFT) and Møller–Plesset perturbation theory (MP2) with the 6–31G(d), 6–31++G(d), 6–31G(d,p), 6–31+G(d,p), 6–31++G(d,p), 6–311G(d,p) and 6–311+G(d,p) basis sets were used to study stereoelectronic hyperconjugative interactions and the mechanism of the chair–chair conformational interconversion in 1,2,3‐trithiacyclohexane (1,2,3‐trithiane). The relative energies, enthalpies, entropies, free energies and structural parameters of the chair, 1,4‐twist and 2,5‐twist conformers, a distorted 1,4‐boat transition state and a 2,5‐boat transition state were calculated. The HF calculated energy difference (ΔE) between the chair conformer of 1,2,3‐trithiane and the distorted 1,4‐boat transition state was 10.59 kcal mol−1 (1 kcal=4.184 kJ). The 1,4‐twist conformer and the 2,5‐boat transition state are close in energy, as are the 2,5‐twist conformer and the distorted 1,4‐boat transition state. B3LYP/6–311+G(d,p) calculated the chair conformer of 1,2,3‐trithiane to be 5.83, 10.09, and 5.96 kcal mol−1, respectively, lower in energy than the 1,4‐twist conformer, 2,5‐twist conformer and 2,5‐boat transition state. Intrinsic reaction coordinate (IRC) calculations were used to connect the transition state between the chair conformer and the 1,4‐twist conformer. B3LYP/6–31+G(d,p) and B3LYP/6–311+G(d,p) calculated this transition state to be 14.25 kcal mol−1 higher in energy than the chair conformer. In the chair conformer, the respective C4—H and C6—H bond lengths are equal, but the C5—Heq bond is longer than the C5—Hax bond. In the 1,4‐twist conformer, the C4—Hiso bond lengths are equal, the C5—Hψeq bond is longer than the C5—Hψax bond and the C6—H bond lengths are equal. In the 2,5‐twist conformer, equal C—H bond lengths are found at C4 and at C5, but the C6—Hψeq bond is longer than the C6—Hψax bond. Copyright © 2003 John Wiley & Sons, Ltd.Additional material for this paper is available in Wiley Intersciene
Mechanisms of the substitution reactions of phosphoramidites and their congeners
Authors: Nurminen Erkki , Lönnberg Harri 
Published: December 2003

AbstractMechanistic research on the nucleophilic substitution of trivalent phosphorus compounds is reviewed with emphasis on the reactions of phosphoramidites. The reactivity of these compounds towards hydroxyl groups is utilized, for instance, in the coupling step of the modern automated solid‐support synthesis of oligonucleotides. Growing interest in the large‐scale synthesis of oligonucleotides as antisense‐strategy drugs has increased the demand for relevant mechanistic research that has considerably improved our understanding of phosphoramidite alcoholysis reaction during the last few years. The review also covers phosphites that are formed as products of this reaction and also phosphorohalidites, azolyl phosphonites and P(III) azolidites that serve as its intermediates. Mechanisms of reactions of phosphoramidites with azoles and carbozylic acids are included together with those of halogenation and transamidation. Alternative reaction mechanisms published in the literature for substitution reactions of P(III) compounds range from dissociative to concerted and associative pathways while different types of activation have been suggested. Reactions of phosphoramidites with alcohols have been shown to be subject to both nucleophilic and acid catalysis and most likely proceed with a concerted mechanism of dissociative character. The consequences of these conclusions for the development of the phosphoramidite approach of oligonucleotide synthesis are also discussed. Copyright © 2003 John Wiley & Sons, Ltd.
Determination of the hydrogen‐bond basicity of weak and multifunctional bases: the case of lindane (γ‐hexachlorocyclohexane)
Authors: Ouvrard Carole , Luçon Maryvonne , Graton Jérôme , Berthelot Michel , Laurence Christian 
Published: December 2003

AbstractWe made use of four methods for determining the hydrogen‐bond (HB) basicity of lindane (γ‐hexachlorocyclohexane): (i) experimental Fourier transform IR measurement of a sum of individual 1:1 equilibrium constants for the formation of 1:1 4‐fluorophenol‐lindane hydrogen‐bonded complexes in CCl4; (ii) calculation of the overall HB basicity from octanol–water partition coefficients; (iii) correlation of the HB basicity of chloroalkanes with the electrostatic potentials around chlorine atoms; and (iv) correlation of the HB basicity of chloroalkanes with the computed enthalpy of their complexes with hydrogen fluoride. It is consistently found that lindane remains a weak HB base because multifunctionality cannot fully compensate for the electron‐withdrawing inductive effects that chlorine atoms exert over one another. Actually, only five chlorine atoms behave as HB acceptors, one axial chlorine being deactivated by inductive effects. Stereoelectronic effects lead to the formation of three‐centered hydrogen bonds. Copyright © 2003 John Wiley & Sons, Ltd.
Oxidation of substituted 2‐furaldehydes by quinolinium dichromate: a kinetic study
Authors: Chaubey Girija S. , Kharsyntiew Bansiewdor , Mahanti Mahendra K. 
Published: December 2003

AbstractThe kinetics of oxidation of substituted 2‐furaldehydes by quinolinium dichromate in sulfuric acid, using 50% acetic acid as the solvent, was studied. The rate of the reaction was first order in each of the substrate, oxidant and acid. The kinetic data are discussed with reference to the aldehyde hydration equilibria. The kinetic results support a mechanistic pathway proceeding via a rate‐determining oxidative decomposition of the chromate ester of the aldehyde hydrate. Copyright © 2003 John Wiley & Sons, Ltd.
Identical kinetic behavior of dichromates and halochromates of heterocyclic bases: oxidations of pentan‐1‐ol
Authors: Karunakaran Chockalingam , Suresh Sadasivam 
Published: December 2003

AbstractThe oxidations of pentan‐1‐ol with 12 dichromates, fluorochromates, chlorochromates and bromochromate of heterocyclic bases in acidic medium exhibit identical kinetic behavior; first order each with respect to the chromium(VI) reagents and alcohol, and are acid catalyzed. The Arrhenius plots show two common points of intersection, one by the three quinolinium complexes and the other by the rest, suggesting the involvement of the quinolinium moiety in the transition state to be different from that of the other heterocyclic bases. Copyright © 2003 John Wiley & Sons, Ltd.
Evapotranspiration covers: An innovative approach to remediate and close contaminated sites
Authors: Madalinski Kelly L. , Gratton Danielle N. , Weisman Richard J. 
Published: December 2003

AbstractA new, cost‐effective option for the remediation and final closure of contaminated landfill sites gaining interest among environmental
professionals is the evapotranspiration (ET) cover. Unlike current covers that use hydraulic barriers to prevent water from reaching the waste,
ET covers rely on the simple concept of using water balance components to meet this goal. Depending on site conditions and other factors, ET covers may
be less costly to construct, while still offering performance equivalent to conventional covers. While ET covers are being proposed, tested, or installed
at a number of contaminated sites, field performance data remain limited. To address the need for more information, the U.S. Environmental Protection
Agency (EPA) has been conducting several efforts to make available more information about this promising alternative solution. This article
summarizes these efforts and provides information on the current status of using ET covers at contaminated sites. © 2003 Wiley Periodicals, Inc.
Performance of conventional remedial technology for treatment of MTBE and benzene at UST sites in Kansas
Authors: Hattan Greg , Wilson Barbara , Wilson John T. 
Published: December 2003

AbstractGroundwater at most underground storage tank (UST) spills sites in Kansas contains both methyl tertiary butyl ethylene (MTBE)
and benzene, and both contaminants must be effectively treated to close the sites. Soil vacuum extraction, air sparging, and excavation are the most
common treatment technologies in Kansas. To compare the relative performance of these conventional remedial technologies for treating MTBE as
compared to benzene, 66 sites in the Kansas UST Trust Fund were identified that had initial concentrations of both MTBE and benzene above the
reporting limit of 1 μg/L, and that had at least two rounds of analytical data. Sites were excluded from the comparison if the monitoring
wells had free product. Of the 66 sites, 15 had met the clean‐up goal for benzene, and 50 had met the goal for MTBE. The extent of treatment
for MTBE and benzene was calculated as the ratio of the highest concentration in any well at the site in the most recent round of sampling to the
maximum concentration in any well at the site in the previous rounds of sampling. The extent of treatment was greater for MTBE (statistically
significant at p = 0.032). The geometric mean of the extent of treatment in the 66 sites was 0.057 for MTBE, compared to 0.14 for
benzene. In Kansas, conventional technologies removed MTBE from the source areas of groundwater plumes at least as effectively as they removed
benzene. © 2003 Wiley Periodicals, Inc.
Review: The Benefits and Applications of Bioinspired Flight Capabilities
Authors: Thakoor Sarita , Cabrol Nathalie , Lay Norman , Chahl Javaan , Soccol Dean , Hine Butler , Zornetzer Steven 
Published: December 2003

AbstractThis paper addresses the challenges of flight on Mars that at this time have the same element of novelty as flight on Earth itself was a novelty in the Kitty Hawk era almost 100 years ago, details the scientific need for such flyers, highlights the bioinspired engineering of exploration systems (BEES) flyer development and finally describes a few viable mission architecture options that allow reliable data return from the BEES flyers using the limited telecom infrastructure that can be made available with a lander base to orbiter combination on Mars. Our recent developments using inspiration from biology that are enabling the pathway to demonstrate flight capability for Mars exploration are described. These developments hold substantial spin‐offs for a variety of applications both for NASA and DoD. Unmanned exploration to date suggests that Mars once had abundant liquid water (considered essential for life as we know it). It is not clear what transpired on the Martian climate to have turned the planet into the desert that it is today. Developing a comprehensive understanding of the past and present climatic events for Mars may provide important information relevant to the future of our own planet. Such exploration missions are enabled using the BEES technology. © 2003 Wiley Periodicals, Inc.
Position/Force Control of an Underwater Mobile Manipulator
Authors: Lapierre Lionel , Fraisse Philippe , Dauchez Pierre 
Published: December 2003

AbstractThis paper proposes a new control method applied to an underwater vehicle equipped with a robot manipulator. This control method is based on force control to stabilize the platform when the manipulator works in free or constrained space. The torque produced by the arm on the platform is estimated with a force sensor installed between the base of the manipulator and the vehicle. This allows correcting the position errors of the platform using an external force control loop. This paper presents this control law and shows some simulation results. © 2003 Wiley Periodicals, Inc.
Optimal Velocity Planning of Wheeled Mobile Robots on Specific Paths in Static and Dynamic Environments
Authors: Prado María , Simón Antonio , Carabias Enrique , Perez Ana , Ezquerro Francisco 
Published: December 2003

AbstractThis paper deals with optimal temporal‐planning of wheeled mobile robots (WMRs) when navigating on predefined spatial paths. A method is proposed to generate a time‐optimal velocity profile for any spatial path in static environments or when mobile obstacles are present. The method generates a feasible trajectory to be tracked by fully exploiting velocity, acceleration and deceleration boundaries of the WMR, and by ensuring the continuity of the velocity and acceleration functions. As an additional benefit for the tracking process the jerk is also bounded. The algorithm is not time consuming, since it mostly uses closed mathematical expressions, nonetheless iteration strategies are presented to solve specific situations. However, such situations are not expected to occur when the spatial paths are planned as smooth curves. The success of the algorithm was tested by experimental and simulation results on the WMR “RAM.” © 2003 Wiley Periodicals, Inc.
A multistage model for maternal morbidity during antenatal, delivery and postpartum periods
Authors: Islam M. Ataharul , Chowdhury Rafiqul Islam , Chakraborty Nitai , Bari Wasimul 
Published: December 2003

AbstractThere is acute dearth of information regarding factors affecting complications during different stages of childbearing in Bangladesh. This study employs a multistage model that involves transitions at different stages to complications. The proposed model appears to display more meaningful explanation concerning the impact of different factors on the incidence of complications taking into account types of transitions. Two alternative models are also presented in this paper in order to demonstrate possible simplifications of the proposed model. This study uses data from a prospective survey on Maternal Morbidity in Bangladesh. The survey was conducted during the period 11 1992–12 1993. A total of 1020 pregnant women were followed during pregnancy, delivery and 90 days after delivery. This study reveals some very important findings regarding the potential impact of antenatal visits, economic status, whether the index pregnancy was desired or not and number of pregnancies prior to the index pregnancy. It is observed that slightly more than 50 per cent of the women suffer from at least one of the major complications (haemorrhage, excessive vomiting, oedema and fits/convulsion) during pregnancy. It is noteworthy that if a woman suffers from one or more of the major complications during pregnancy, then it is more likely that she will suffer from complications during delivery. This study reveals that the women who suffer from one or more of the major complications during pregnancy are expected to have a substantially higher risk of suffering from complications during postpartum period, irrespective of no complications or complications during delivery. Generally speaking, higher economic status can reduce the complications at the postpartum stage, although women belonging to higher economic status may suffer from complications during pregnancy and delivery at a higher rate. It is surprising that antenatal visit is positively associated with incidence of complications during pregnancy and delivery, but antenatal visit reduces complications at the postpartum stage. Copyright © 2004 John Wiley & Sons, Ltd.
Meta‐analysis for trend estimation
Authors: Shi Jian Qing , Copas J. B. 
Published: December 2003

AbstractGrouped dose measures, heterogeneity and publication bias are three major problems for meta‐analysis in trend estimation. In this paper, we propose a model that allows for arbitrarily aggregated dose levels, and show that the resulting estimates and standard errors can be quite different from those given by the usual assigned value method. Based on fitting a model to the funnel plot, we discuss a method for random‐effects sensitivity analysis that deals with the problems of heterogeneity and publication bias. A meta‐analysis of epidemiological studies on the effect of alcohol on the risk of breast cancer is used to illustrate the method. Our analysis suggests that the rate of increase in risk with alcohol consumption is substantially less than has been previously suggested. Copyright © 2004 John Wiley & Sons, Ltd.
Small sample estimation of relative accuracy for binary screening tests
Authors: Alonzo Todd A. , Braun Thomas M. , Moskowitz Chaya S. 
Published: December 2003

AbstractComparing the accuracy of two screening tests is ideally achieved by administering both tests as well as a gold standard test to all study subjects. In practice, a more ethical screen positive study design is often used, one that requires gold standard determination only for subjects that screen positive on either test under investigation. Although it is not possible to quantify the absolute accuracy of each test with such a design,the relative accuracy of the tests can be estimated. Since relative accuracy estimation has poor small sample properties, adjusted estimators based on adding constants to the observed data have been proposed. The adjusted estimators have the advantage that they yield point and variance estimates of relative accuracy in all settings. However, we show through both theory and numerical examples that adding constants to the data can be beneficial or detrimental to small sample performance. Furthermore, the performance of the adjusted estimator depends not only on the magnitude of the constant but also on parameters that cannot be estimated with data from a screen positive study, making selection of an optimal constant difficult in practice. We also examine the performance of the adjusted estimator using data from a study comparing the accuracy of two screening tests for cervical cancer. Copyright © 2004 John Wiley & Sons, Ltd.