bluuebunny/crossref_metadata_2025 huggingface dataset:
Minimum fuel powered dynamic soaring of unmanned aerial vehicles utilizing wind gradients
Authors: Zhao Yiyuan J. , Qi Ying Celia
Published: November 2004

This paper studies optimal powered dynamic soaring flights of unmanned aerial vehicles (UAVs) that utilize low‐altitude wind gradients for reducing fuel consumptions. Three‐dimensional point‐mass UAV equations of motion are used, and linear wind gradients are assumed. Fundamental UAV performance parameters are identified through the normalization of the equations of motion. In particular, a single wind condition parameter is defined that represents the combined effect of air density, UAV wing loading, and wind gradient slope on UAV flight. An optimal control problem is first used to determine bounds on wind conditions over which optimal powered dynamic soaring is meaningful. Then, powered UAV dynamic soaring flights through wind gradients are formulated as non‐linear optimal control problems. For a jet‐engined UAV, performance indices are selected to minimize the average thrust required per cycle of powered dynamic soaring that employs either variable or constant thrust. For a propeller‐driven UAV, in comparison, performance indices are selected to minimize the average power required per cycle of powered dynamic soaring with either variable or constant power. All problem formulations are subject to UAV equations of motion, UAV operational constraints, proper initial conditions, and terminal conditions that enforce a periodic flight. These optimal control problems are converted into parameter optimization with a collocation method and solved numerically using the parameter optimization software NPSOL. Analytical gradient expressions are derived for the numerical solution process. Extensive numerical solutions are obtained for a wide range of wind conditions and UAV performance parameters. Results reveal basic features of powered dynamic soaring flights through linear wind gradients. Copyright © 2004 John Wiley & Sons, Ltd.
Polyhedral risk measures in electricity portfolio optimization
Authors: Eichhorn Andreas , Römisch Werner , Wegner Isabel
Published: November 2004

We compare different multiperiod risk measures taken from the class of polyhedral risk measures with respect to the effect they show when used in the objective of a stochastic program. For this purpose, simulation results of a stochastic programming model for optimizing the electricity portfolio of a German municipal power utility are presented and analyzed. This model aims to minimize risk and expected overall cost simultaneously. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Robust Process Control by Dynamic Stochastic Programming
Authors: Steinbach Marc C.
Published: November 2004

Unnecessarily conservative behavior of standard process control techniques can be avoided by stochastic programming models when the distribution of random disturbances is known. In an earlier study we have investigated such an approach for tank level constraints of a distillation process. Here we address techniques that have accelerated the numerical solution of the large and expensive stochastic programs by a factor of six, and then present a refined optimization model for the same application. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On Two‐step Schemes for SDEs with Small Noise
Authors: Buckwar Evelyn , Winkler Renate
Published: November 2004

We consider linear multi‐step methods for stochastic differential equations and present a theorem ensuring their numerical stability and strong convergence. We use this to study the properties of two‐step schemes for stochastic differential equations with small noise. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the Optimization of Non‐Negative Density Solutions of Stationary Fokker‐Planck Equations
Authors: Wedig Walter V.
Published: November 2004

Classical solution methods of Fokker‐Planck equations (see e.g. [1], [2], [3]) lead to negative densities at least in the tales where the density solutions strongly approach zero. To avoid these inconsistencies the paper proposes to apply central differences schemes in combination with large‐scaled quadratic optimization programming [4]. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling and Optimization of a Silicon Tuning Fork Gyroscope
Authors: Kugi A. , Thull D. , Seidel H.
Published: November 2004

This contribution deals with the systematic derivation of an analytical model for a silicon tuning fork gyroscope with piezoelectric drive and piezoresistive read‐out. The mathematical model serves as a basis for optimizing the overall sensor structure, for testing the electronic circuitry and for investigating the influence of disturbances, e.g. due to fabrication tolerances, on the measurement quality. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Improved error estimates for a Maxwell‐Landau‐Lifschitz system
Authors: Slodička Marián , Cimrák Ivan
Published: November 2004

We study Maxwell's system coupled with the Landau‐Lifshitz (LL) equation. We consider the nonlinear dissipative case with a neglected exchange field. For a recent numerical scheme conserving magnitude of the magnetization we derive new error estimates and establish a better rate of convergence. These theoretical results are demonstrated on a numerical example. For computations we use the software package ALBERT. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of UV irradiation on physico‐mechanical properties of EPDM/buckminsterfullerene composite
Authors: Jin Wonseop , Kader M. Abdul , Ko Weon‐Bae , Nah Changwoon
Published: November 2004

Ethylene propylene diene rubber‐fullerene (EPDM/C60) composite, partially crosslinked by ultraviolet (UV) radiation, was prepared and characterized for crosslink density, mechanical properties and thermal behavior. FT‐IR analysis showed peak disappearance at 1688 cm−1, corresponding to the unsaturation of EPDM, and the appearance of new peaks relating to the formation of oxidation products of C60, such as epoxide, keto, aldehyde and carboxylic groups. Solubility studies demonstrated the dissolution of pristine EPDM in toluene even after a longer period of UV exposure, whereas EPDM/C60 composite became insoluble and/or swollen after 6 hr of UV exposure, indicating the formation of partial crosslinking between EPDM and C60. Differential scanning calorimetry (DSC) measurements revealed an increase in the glass transition temperature peak of UV‐cured EPDM. Thermogravimetric analysis (TGA) showed that UV exposure reduced the thermal decomposition temperature of EPDM/C60, pristine EPDM and dicumyl peroxide (DCP)‐cured EPDM. The modulus, tensile stress and elongation at break of EPDM/C60 composites were greatly influenced by the duration of UV irradiation. Comparison of UV‐cured EPDM/C60 composite with DCP‐cured EPDM confirmed the superior strength properties of the former system. Copyright © 2004 John Wiley & Sons, Ltd.
HPLC investigation of water soluble ternary polyacrylic acid‐Cu2+‐protein complexes
Authors: Taşdelen Betül Dinçer , Bayülken Seval
Published: November 2004

In this present work, complex formation of polyacrylic acid (PAA) with bovine serum albumin (BSA) in the presence of divalent copper ions (Cu2+) was investigated using high performance liquid chromatography (HPLC). HPLC results determined the most suitable metal concentration and protein/polymer ratio for maximum complex formation between polymer and protein molecules. Copyright © 2004 John Wiley & Sons, Ltd.
Pathogen‐induced actin filament rearrangement in infectious diseases
Authors: Rottner Klemens , Lommel Silvia , Wehland Jürgen , Stradal Theresia EB
Published: November 2004

Host defence mechanisms involve the establishment and maintenance of numerous barriers to infectious microbes, including skin and mucosal surfaces, connective tissues, and a sophisticated immune system to detect and destroy invaders. Defeating these defence mechanisms and breaching the cell membrane barrier is the ultimate challenge for most pathogens. By invading the host and, moreover, by penetrating into individual host cells, pathogens gain access to a protective niche, not only to avoid immune clearance, but also to replicate and to disseminate from cell to cell within the infected host. Many pathogens are accomplishing these challenges by exploiting the actin cytoskeleton in a highly sophisticated manner as a result of having evolved common as well as unique strategies. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Second‐trimester prenatal screening markers for Down syndrome in women with insulin‐dependent diabetes mellitus
Authors: Huttly Wayne , Rudnicka Alicja , Wald Nicholas J.
Published: November 2004

Published studies have shown that some serum markers used in screening for Down syndrome tend to be lower among women with insulin‐dependent diabetes mellitus (IDDM). On this basis, many screening programmes adjust the marker levels to take account of this difference. Recent studies suggested that the marker levels were not different, and so adjustment may no longer be needed, possibly because of better diabetic control. Data from a prenatal screening programme for Down syndrome were examined to see whether the median values of second‐trimester screening markers were still reduced in pregnant women with IDDM. A total of 366 women with IDDM singleton pregnancies without Down syndrome were identified from the screening programme at Barts from 1989 to 2002. After allowing for maternal weight, the median multiples of the median (MoM) for IDDM‐unaffected singleton pregnancies were as follows: 0.88 (95% confidence interval 0.84–0.93) for alphafetoprotein (AFP), 0.95 (0.91–0.99) for unconjugated oestriol (uE3), 0.90 (0.80–1.01) for total human chorionic gonadotrophin (total hCG), 0.98 (0.88–1.08) for free β‐hCG, and 0.99 (0.89–1.10) for inhibin‐A.

The median levels for AFP and uE3 were statistically significantly lower in pregnant women with IDDM. The other markers were not significantly different in women with and without IDDM. There remains a case for adjusting AFP and uE3 levels in women with IDDM in prenatal screening programmes for Down syndrome. Copyright © 2004 John Wiley & Sons, Ltd.
Prenatal diagnosis of primary anophthalmia with a 3q27 interstitial deletion involving SOX2
Authors: Guichet Agnès , Triau Stéphane , Lépinard Catherine , Esculapavit Chantal , Biquard Florence , Descamps Philippe , Encha‐Razavi Férechté , Bonneau Dominique
Published: November 2004

We report an interstitial deletion of chromosome 3q26‐q28 in a fetus in which anophthalmia had been detected prenatally. FISH analysis, using BAC clones encompassing the SOX2 locus, showed that SOX2 gene was involved in the chromosomal breakpoint of the deletion. This case confirms that haploinsufficiency for SOX2 plays a crucial role in human eye development and emphasizes the necessity of careful chromosomal analysis, including FISH analysis of the 3q region, in case of prenatal discovery of anophthalmia. Copyright © 2004 John Wiley & Sons, Ltd.
Self‐evaluation
Authors: Wilbur Colburn S.
Published: November 2004

Every foundation should spend some time looking at its mission, goals, processes, and effectiveness. With the right motivation and willingness to listen to criticism, foundation leaders can improve relationships within their organization and with others.
Von der Freiheit in der Welt der Quarks
Authors: Bartels Jochen
Published: November 2004

Die Schwedische Akademie der Wissenschaften vergab in diesem Jahr den Physik‐Nobelpreis zu gleichen Teilen an die amerikanischen Physiker David Gross, David Politzer und Frank Wilczek. Sie würdigte damit ihre theoretischen Arbeiten zur asymptotischen Freiheit in der starken Wechselwirkung.
Die Entdeckung des “trägen” Gases
Authors: Jacobi Manfred
Published: November 2004

Im Jahr 1904 erhielt der britische Physiker Lord Rayleigh (John William Strutt, 1842 bis 1919) den Nobelpreis für seine Untersuchungen über die Dichte von Gasen und die Entdeckung des Edelgases Argon.
Thermische Muster an Wänden
Authors: Schlichting H.‐Joachim
Published: November 2004

Die Natur bringt manchmal erstaunliche Muster hervor, hinter denen sich interessante physikalische Vorgänge verbergen. Im vorliegenden Fall geht es um thermische Muster. Sie entstehen durch thermische Bedingungen an Begrenzungen von Wänden.
Die Messung des Kilogramms
Authors: Heering Peter
Published: November 2004

Während der französischen Revolution wurden der Meter und das Kilogramm als Basiseinheiten neu definiert. Bis heute muss die Basiseinheit der Masse als einzige noch über einen Prototyp realisiert werden.
Differential expression profiling of human pancreatic adenocarcinoma and healthy pancreatic tissue
Authors: Lu ZhaoHui , Hu LiPing , Evers Stefan , Chen Jie , Shen Yan
Published: November 2004

Due to poor prognosis and lack of effective treatment, pancreatic carcinoma (PC) is a devastating disease. With the goal of contributing to an improved detection, prevention and treatment of the disease, a comparative proteome analysis of PC and normal tissue was carried out. Paired tissue extracts from 12 patients (pancreatic adenocarcinoma and adjacent healthy tissue) were separated by two‐dimensional electrophoresis. Differential protein expression was analyzed by gel comparison with the help of image analysis software. The differentially expressed spots were identified by matrix‐assisted laser desorption/ionization‐time of flight mass spectrometry. Seventy proteins were more strongly expressed (mostly two‐fold or more) in cancerous tissue, while 41 were stronger in normal pancreas respectively. Those spots highly expressed in PC were confirmed in gels from independent individual samples. Among them were several cytoskeletal proteins, small GTP‐binding proteins, and members of the S100 protein family etc. Nine proteins had been reported in previous nuclear acid‐based studies. The levels of two proteins were confirmed by immunohistochemistry. One of them, fascin, was detected in 13 out of 21 carcinoma and negative in all normal pancreas samples. Moreover, fascin expression was related to the differentiation of pancreatic carcinoma.
Global proteomic approach unmasks involvement of keratins 8 and 18 in the delivery of cystic fibrosis transmembrane conductance regulator (CFTR)/ΔF508‐CFTR to the plasma membrane
Authors: Davezac Noélie , Tondelier Danielle , Lipecka Joanna , Fanen Pascale , Demaugre France , Debski Janusz , Dadlez Michal , Schrattenholz André , Cahill Michael A. , Edelman Aleksander
Published: November 2004

Cystic fibrosis (CF) is a genetic disease caused by mutations in the CF gene (cftr). Physiologically, CF is characterized by an abnormal chloride secretion in epithelia due to a dysfunction of a mutated cystic fibrosis transmembrane conductance regulator (CFTR). CFTR is a cAMP‐dependent chloride channel whose most frequent mutation, ΔF508, leads to an aberrantly folded protein which causes a dysfunction of the channel. However, a growing number of reports suggest that modifier genes and environmental factors are involved in the physiology of CF. To identify proteins whose expression depends on wild‐type WT‐CFTR or ΔF508‐CFTR, we chose a global proteomic approach based on the use of two‐dimensional gel electrophoresis (2‐DE) and mass spectrometry. The experiments were carried out with HeLa cells stably transfected with WT‐CFTR (pTCFWT) or ΔF508‐CFTR (pTCFΔF508). These experiments unmasked keratin 8 (K8) and 18 (K18) which were differentially expressed in pTCFWT vs. pTCFΔF508. An immunoblot of K18 confirmed the 2‐DE results. Intracellular localization experiments of WT‐CFTR, ΔF508‐CFTR, K8, and K18 suggest that the expression of these proteins are linked, and that the concentrations of K8 and K18 and/or their distribution may be involved in the traffic of WT‐CFTR/ΔF508‐CFTR. A functional assay for CFTR revealed that specifically lowering K18 expression or changing its distribution leads to the delivery of functional ΔF508‐CFTR to the plasma membrane. This work suggests a novel function of K18 in CF.
Improved mass spectrometric identification of gel‐separated hydrophobic membrane proteins after sodium dodecyl sulfate removal by ion‐pair extraction
Authors: Zischka Hans , Gloeckner Christian Johannes , Klein Christian , Willmann Stefanie , Swiatek‐de Lange Magdalena , Ueffing Marius
Published: November 2004

Separation and identification of hydrophobic membrane proteins is a major challenge in proteomics. Identification of such sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE)‐separated proteins by peptide mass fingerprinting (PMF) via matrix‐assisted laser desorption/ionization‐time of flight (MALDI‐TOF) is frequently hampered by the insufficient amount of peptides being generated and their low signal intensity. Using the seven helical transmembrane‐spanning proton pump bacteriorhodopsin as model protein, we demonstrate here that SDS removal from hydrophobic proteins by ion‐pair extraction prior to in‐gel tryptic proteolysis leads to a tenfold higher sensitivity in mass spectrometric identification via PMF, with respect to initial protein load on SDS‐PAGE. Furthermore, parallel sequencing of the generated peptides by electrospray ionization‐mass spectrometry (ESI‐MS) and tandem mass spectrometry (MS/MS) was possible without further sample cleanup. We also show identification of other membrane proteins by this protocol, as proof of general applicability.
Vascular proteomics: Linking proteomic and metabolomic changes
Authors: Mayr Manuel , Mayr Ursula , Chung Yuen‐Li , Yin Xiaoke , Griffiths John R. , Xu Qingbo
Published: November 2004

Cardiovascular diseases constitute the largest of death in the Western world. Various stressors, including elevated blood pressure, smoking, diabetes, and hypercholesterolemia directly or indirectly damage the vessel wall, eventually inducing arterial stiffness (arteriosclerosis) and lipid accumulation (atherosclerosis). However, the molecular mechanisms of atheroma formation are not yet fully clarified. While many investigators have used proteomic techniques to study cardiac diseases, vascular proteomics is still in its infancy. The present review highlights studies, in which proteomics has been successfully applied to study protein alterations in the vasculature. Furthermore, we will summarize our recent progress in combining proteomic and metabolomic techniques to reveal protein and metabolite alterations in the cardiovascular system: two‐dimensional (2‐D) gel electrophoresis proved to be highly complementary to nuclear magnetic resonance (NMR) spectroscopy, in that post‐translational modifications of the most abundant enzymes were displayed on 2‐D gels while NMR spectroscopy revealed changes in the corresponding metabolites. Importantly, the simultaneous assessment of protein and metabolite changes translated purely descriptive proteomic and metabolomic profiles into a functional context and provided important insights into pathophysiological mechanisms that would not have been obtained by other techniques.
Towards a comprehensive understanding of Bacillus subtilis cell physiology by physiological proteomics
Authors: Hecker Michael , Völker Uwe
Published: November 2004

Using Bacillus subtilis as a model system for functional genomics, this review will provide insights how proteomics can be used to bring the virtual life of genes to the real life of proteins. Physiological proteomics will generate a new and broad understanding of cellular physiology because the majority of proteins synthesized in the cell can be visualized. From a physiological point of view two major proteome fractions can be distinguished: proteomes of growing cells and proteomes of nongrowing cells. In the main analytical window almost 50% of the vegetative proteome expressed in growing cells of B. subtilis were identified. This proteomic view of growing cells can be employed for analyzing the regulation of entire metabolic pathways and thus opens the chance for a comprehensive understanding of metabolism and growth processes of bacteria. Proteomics, on the other hand, is also a useful tool for analyzing the adaptational network of nongrowing cells that consists of several partially overlapping regulation groups induced by stress/starvation stimuli. Furthermore, proteomic signatures for environmental stimuli can not only be applied to predict the physiological state of cells, but also offer various industrial applications from fermentation monitoring up to the analysis of the mode of action of drugs. Even if DNA array technologies currently provide a better overview of the gene expression profile than proteome approaches, the latter address biological problems in which they can not be replaced by mRNA profiling procedures. This proteomics of the second generation is a powerful tool for analyzing global control of protein stability, the protein interaction network, protein secretion or post‐translational modifications of proteins on the way towards the elucidation of the mystery of life.
Multifunctional coupling agents: Synthesis and model reactions
Authors: Jakisch L. , Komber H. , Böhme F.
Published: November 2004

New multifunctional coupling agents with one 2‐oxazoline group, one oxazinone group, and one allyl ether group were prepared. It was shown by means of model reactions that under the conditions of reactive extrusion, the 2‐oxazoline group and the oxazinone group reacted selectively with carboxylic groups and amino groups, respectively. The allyl ether group remained unaffected under the reaction conditions chosen. As a model reaction, the conversion of the coupling agents with 11‐aminoundecanoic acid resulted in the formation of an allyloxy‐functionalized poly(ester amide). The reaction could be performed stepwise, in the course of which the reaction of the amino group proceeded at 110 °C in solution, whereas the reaction of the carboxylic group was performed in the melt at 220 °C. Furthermore, the utilization of the coupling agents for the preparation of telechelic poly(propylene glycol) with one oxazoline group and one allyl ether group on each chain end was described. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 655–667, 2003
Synthesis and properties of π‐conjugated dithiafulvene oligomers by addition of a monofunctionalized compound
Authors: Naka Kensuke , Gelover‐Santiago Adriana , Uemura Takashi , Chujo Yoshiki
Published: November 2004

Dithiafulvene oligomers (3) were prepared by cycloaddition polymerization of aldothioketenes with their alkynethiol tautomers derived from 1,4‐diethynylbenzene (2) with the addition of 1‐ethynyl‐4‐methylbenzene (1) as a monofunctionalized compound. Different feed ratios of 2/1were used to control the molecular weights of 3. The structures of 3 were confirmed by IR and 1H NMR spectroscopies in comparison with those of 2‐(4‐tolylidene)‐4‐tolyl‐1,3‐dithiol (4) as a model compound, which was obtained by the treatment of lithium 2‐tolylethynethiolate with water in Et2O. The number‐average degree of polymerization (DP) and the number‐average molecular weight were measured by gel permeation chromatographic and 1H NMR analysis. DP increased with an increasing feed ratio of 2/1. The ultraviolet–visible spectra of 3 in diluted acetonitrile showed that the absorption maxima of 3 increased with an increasing DP of 3. These redshifts are ascribed to an effective expansion of the π‐conjugation system in 3. The oligomers exhibited a maximum conjugation length of seven repeating units. The redox properties of 3 were examined by cyclic voltammetry. The oxidation half‐peak potentials (Ep/2) of 3 were slightly cathodically shifted with increasing DP. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 708–715, 2003
Bereavement outcomes for parents who lose a child to cancer: Are place of death and sex of parent associated with differences in psychological functioning?
Authors: Goodenough Belinda , Drew Donna , Higgins Susan , Trethewie Susan
Published: November 2004

Despite increasing cure rates, cancer is a leading cause of non‐accidental death in childhood. Models of psychosocial care in pediatric cancer may therefore need to address bereavement planning for a ‘minority group’ of parents (approximately 25%) for whom cure of their child is not possible. This study addresses a gap in knowledge concerning long‐term bereavement and psychological outcomes for parents, as a function of the sex of the parent and the place of the child's death: home versus hospital. Fifty Australian parents (25 father–mother dyads), whose child had died at least 1 year prior to study participation, independently completed measures of psychological functioning (depression, anxiety and stress), family functioning, and pathological grieving (separation distress, and traumatic distress). The results showed some support for a hypothesized interaction between place of death and sex of parent. Fathers reported significantly higher levels of depression, anxiety and stress when the child died in hospital rather than at home. By way of contrast, differences for mothers as function of place of death were not reflected in psychological outcomes but were more closely tied to symptoms of pathological grieving. The findings are discussed with respect to the needs for services for surviving adult family members, especially for fathers who may have an enhanced psychological vulnerability after the death of a child in hospital rather than at home. Copyright © 2004 John Wiley & Sons, Ltd.
Specific DNA recognition by the Antp homeodomain: MD simulations of specific and nonspecific complexes
Authors: Gutmanas Aleksandras , Billeter Martin
Published: November 2004

Four molecular dynamics simulation trajectories of complexes between the wild‐type or a mutant Antennapedia homeodomain and 2 DNA sequences were generated in order to probe the mechanisms governing the specificity of DNA recognition. The starting point was published affinity measurements showing that a single protein mutation combined with a replacement of 2 base pairs yields a new high‐affinity complex, whereas the other combinations, with changes on only 1 macromolecule, exhibited lower affinity. The simulations of the 4 complexes yielded fluctuating networks of interaction. On average, these networks differ significantly, explaining the switch of affinity caused by the alterations in the macromolecules. The network of mostly hydrogen‐bonding interactions involving several water molecules, which was suggested both by X‐ray and NMR structures of the wild‐type homeodomain and its DNA operator sequence, could be reproduced in the trajectory. More interestingly, the high‐affinity complex with alterations in both the protein and the DNA yielded again a dynamic but very tight network of intermolecular interactions, however, attributing a significantly stronger role to direct hydrophobic interactions at the expense of water bridges. The other 2 homeodomain–DNA complexes, with only 1 molecule altered, show on average over the trajectories a clearly reduced number of protein–DNA interactions. The observations from these simulations suggest specific experiments and thus close the circle formed by biochemical, structural, and computational studies. The shift from a water‐dominated to a more “dry” interface may prove important in the design of proteins binding DNA in a specific manner. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Dust explosion prevention and the critical importance of housekeeping
Authors: Frank Walter L.
Published: November 2004

Two recent, tragic events remind us that the broad topic of high‐energy release events encompasses more than vapor cloud explosions and reactive chemical incidents. Dust explosions also have potential for causing catastrophic harm to personnel and facilities. This paper describes recent, major dust explosions with a particular focus on learnings related to a commonly underconsidered aspect of facility operations—housekeeping. © 2004 American Institute of Chemical Engineers Process Saf Prog 23: 175–184, 2004
Emergency response of toxic chemicals in Taiwan: The system and case studies
Authors: Chen Jenq‐Renn , Hung C.H. , Fan K.S. , Ho T.C. , Chen F.L. , Horng J.J. , Ho S.C. , Chen W.D.
Published: November 2004

In this paper we describe an emergency response system in Taiwan funded by the Taiwan Environmental Protection Administration and consisted of three local response centers held by the Industrial Technology Research Institute, National Yunlin University of Science and Technology, and National Kaohsiung First University of Science and Technology in the north, central, and south part of the island, respectively. The system is set up for the effective and efficient response to incidents involving toxic chemicals, and reducing the potential impact on the environment from these incidents. Case studies are also provided for the incidents. These incidents range from a fire in a chemical plant to a spillage from a tank truck on the road. The responded incidents are analyzed and possible root causes are identified and classified. The information provided should benefit areas with growing industrial development in developing strategies to prevent or reduce the potential impacts from chemical incidents. © 2004 American Institute of Chemical Engineers Process Saf Prog 23: 206–213, 2004
Labour market concentration of Asian ethnic groups in US metropolitan areas: a disaggregated study
Authors: Wang Qingfang
Published: November 2004

Ethnic labour market concentration has been attracting increasing attention in recent years. But the Asian ethnic group has been treated as a homogeneous group in most studies on ethnic labour market segmentation. Using the 1% Public Use Microdata Samples (PUMS) from the metropolitan areas in the United States with the largest Asian populations, this study shows that Asian ethnic groups are quite diverse in their labour market concentrations. Asian Indian, Japanese and Filipino workers are more concentrated in professional and management employment sectors, which generally require higher levels of skill, English proficiency and education. By contrast, Vietnamese, Korean and Chinese groups are more concentrated in the labour‐intensive, semi‐ or low‐skilled manufacturing and personal service sectors. Their concentration patterns are closely related to their human capital characteristics. However, human capital cannot entirely explain the process of labour market choice. Analysis indicates that working with co‐ethnic populations could provide more job opportunities for disadvantaged workers, as a result of social networking. Location factors also impact niche employment choice. Copyright © 2004 John Wiley & Sons, Ltd.
Use of generalized estimating equations in a trial in influenza to explore treatment effects over time
Authors: Keene Oliver N. , Davis Randy L. , Koch Gary G.
Published: November 2004

For trials with repeated measurements of outcome, analyses often focus on univariate outcomes, such as analysis of summary measures or of the last on‐treatment observation. Methods which model the whole data set provide a rich source of approaches to analysis. For continuous data, mixed‐effect modelling is increasingly used. For binary and categorical data, models based on use of generalized estimating equations account for intra‐subject correlation and allow exploration of the time course of response, as well as providing a useful way to account for missing data, when such data can be maintained as missing in the analysis. The utility of this approach is illustrated by an example from a trial in influenza. Copyright © 2004 John Wiley & Sons Ltd.
A Method of Estimating the Process Capability Index from the First Four Moments of Non‐normal Data
Authors: Ding Jianmin
Published: November 2004

A method is presented to estimate the process capability index (PCI) for a set of non‐normal data from its first four moments. It is assumed that these four moments, i.e. mean, standard deviation, skewness, and kurtosis, are suitable to approximately characterize the data distribution properties. The probability density function of non‐normal data is expressed in Chebyshev–Hermite polynomials up to tenth order from the first four moments. An effective range, defined as the value for which a pre‐determined percentage of data falls within the range, is solved numerically from the derived cumulative distribution function. The PCI with a specified limit is hence obtained from the effective range. Compared with some other existing methods, the present method gives a more accurate PCI estimation and shows less sensitivity to sample size. A simple algebraic equation for the effective range, derived from the least‐square fitting to the numerically solved results, is also proposed for PCI estimation. Copyright © 2004 John Wiley & Sons, Ltd.
Combination of Fragmental and Topological Descriptors for QSPR Estimations of Boiling Temperature
Authors: Tsygankova Irina G.
Published: November 2004

The novel QSPR equation for estimation of physicochemical properties of organic substances is proposed. This equation includes contributions depending on the counts of bonds and nonadditive contribution. The nonadditive term is represented as an explicit function of topological distances on the line graph of molecules. The original mathematical form for description of nonadditive contribution is suggested. The application of the derived equation to estimation of normal boiling temperatures for the saturated hydrocarbons (total number of compounds n=198; correlation coefficient r=0.9966; mean square deviation σ=3.4 K) has proved the effectiveness of the proposed approach. The modification of correlation equation is made for estimations of normal boiling temperatures for substances with OH and NH2 groups (n =139; r=0.9971; σ=3.9 K).
A thin chip microsprayer system coupled to Fourier transform ion cyclotron resonance mass spectrometry for glycopeptide screening
Authors: Bindila Laura , Froesch Martin , Lion Niels , Vukelić Željka , Rossier Joël S. , Girault Hubert H. , Peter‐Katalinić Jasna , Zamfir Alina D.
Published: November 2004

A thin polymer microchip was coupled with a Fourier transform ion cyclotron resonance (FTICR) 9.4 T mass spectrometer and the method was optimized in negative ion mode for glycopeptide screening. The interface between the polymer microchip and FTICR mass spectrometer consists of an in‐laboratory conceived and designed mounting system that exhibits robust and controllable alignment of the chip toward the inlet of the mass spectrometer. The particular attribute of the polymer chip coupled to the FTICR mass spectrometer, to achieve an increase in ionization efficiency and sensitivity under the premise of high mass accuracy of detection, is highlighted by the large number of major and minor glycopeptide structures detected and identified in highly heterogeneous mixtures obtained from urine matrices. Glycoforms expressing various saccharide chain lengths ranging from tri‐ to dodecasaccharide, bearing up to three sialic acid moieties, could be detected and assigned based on the accuracy of the mass measurement (average mass deviation below 6 ppm) of their molecular ions. (–)Thin chipESI‐FTICRMS is a potent novel system for glycomic screening of complex mixtures, as demonstrated for identification of singly sialylated O‐glycosylated amino acids and peptides from urine matrices, and could be considered for general applicability in the glycoanalytical field. Copyright © 2004 John Wiley & Sons, Ltd.
Sand exchange between groyne‐field beaches and the navigation channel of the Dutch Rhine: the impact of navigation versus river flow
Authors: Ten Brinke Wilfried B. M. , Schulze Floris H. , van Der Veer Peter
Published: November 2004

The morphodynamics of groyne‐field beaches along the Dutch Rhine was studied from in situ measurements of hydrodynamics and sand transport, aerial photographs, and bed‐level time series. From the analyses, it appeared that groyne‐field beaches experience an alternation of periods of erosion and deposition. The erosion is due to navigation at low to moderate discharge; the deposition is due to floods. On a time scale of a few decades, periods of erosion and deposition are in equilibrium. Navigation‐induced erosion is mainly due to vessels >60 m. The impact of passing vessels on the currents near the banks and the erosion of the beaches increases as underwater volume increases. Individually, loaded barge‐tows have the greatest influence on groyne‐field hydrodynamics and sand transport. On a yearly basis, however, the relatively strong influence of push towing is superseded by the higher frequency of passing motorized vessels. The erosion on a yearly basis, therefore, is driven by the effects of the large motorized vessels. The effects of push towing are negligible.

Underwater volume and passing distance from the bank are the most important parameters of passages, insofar as their effect on groyne‐field beaches is concerned. The effect of underwater volume is clearly reflected in the different behaviour of groyne‐field beaches on the north and south banks. Loaded vessels sailing along the south bank from Rotterdam to Germany have a much greater effect on the beaches on the south bank than do returning vessels, often empty or partly loaded, on the beaches of the north bank. As a result, beach erosion on the south bank is twice as pronounced as the erosion on the north bank. Remarkably, the greater erosion of the beaches observed on the south bank was compensated by a similarly larger deposition during the flood of 1998.

The impact of navigation on groyne‐field beach erosion increased strongly from 1970 to 2001, and probably will have doubled from 1970 to 2010. Copyright © 2004 John Wiley & Sons, Ltd.
Making sustainable development evaluations work
Authors: Becker Joanna
Published: November 2004

The number of sustainable development evaluation methods has proliferated during the last few years. However, they are often time consuming and expensive to conduct, making reiteration, a crucial part of assessing progress, an unappealing and difficult task. Making the results comprehensible and meaningful to the public is also challenging but essential if evaluations are to be translated into policy and action. Moreover, although such evaluations are important in assessing progress towards sustainable development, it may be hard to make them responsive to change, which is synonymous with the concept of development. Change includes both the conditions being assessed and the techniques that are used.

This paper explores the crucial elements for making sustainable development evaluations work using the Bellagio principles as a framework to identify tools that can be used to implement them. These principles are interrelated and taken together can help ensure the effectiveness of sustainable development evaluations. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment.
Monte‐Carlo program for simulating segregation and diffusion utilizing chemical potential calculations
Authors: Joubert H. D. , Swart H. C. , Terblans J. J.
Published: November 2004

The surface segregation phenomenon was simulated by means of a Chemical Potential Monte‐Carlo (CPMC) model, which is based on the Darken model. The chemical potential equations are rewritten to include the segregation energy associated with the surface layer. Simulations involving the change in chemical potential are performed on a two‐dimensional matrix containing two elements: the solute and the solvent elements. A random selection of an atom inside the matrix initiates the model. The change in chemical potential due to an atomic jump of a randomly selected atom to an adjacent layer is calculated. The largest change in chemical potential directs the atomic motion, complying with the conditions associated with lowering of the Gibbs free energy. Inclusion of the segregation energy (for jumps involving the surface layer) limits the number of atomic jumps from the surface layer to the bulk. Simulated segregation profiles generated by the CPMC model were compared with profiles calculated with both the modified Darken and Fick models. These profiles show that the CPMC model successfully describes both the kinetic and equilibrium conditions associated with surface segregation. Copyright © 2004 John Wiley & Sons, Ltd.
Score tests for dose effect in the presence of non‐responders
Authors: Luo Xiaohui , Boos Dennis D. , Tamura Roy N.
Published: November 2004

When only a certain proportion of subjects respond to treatment (‘responders’) or may never experience an event of interest (thus ‘cured’), mixture models often lead to increased understanding of the treatment or disease process. This paper focuses on hypothesis testing in a dose–response framework and shows that increased power is possible by using a mixture model where both the logit of the response rate and the response mean are linear functions of the dose level. Three score tests are developed for testing an overall effect and permutation methods are used to control the type I error. Extensive simulations establish the power properties of the tests and show that our proposed score test has the best performance. The approach is illustrated by a multi‐country clinical trial of rapid acting Intramuscular Olanzapine. Copyright © 2004 John Wiley & Sons, Ltd.
A new parametric model for survival data with long‐term survivors
Authors: Shao Quanxi , Zhou Xian
Published: November 2004

We develop a new parametric model using the three‐parameter Burr XII distribution for the analysis of survival data with long‐term survivors, which includes the previous Weibull mixture model as a special case. The new model is applied to the analysis of a set of leukaemia data for which previous attempts in the literature using traditional parametric models were unsatisfactory due to lack of fit. It is shown that the new model improves the fit to the leukaemia data significantly and is thus capable of providing more credible answers to a variety of statistical inference problems that are of interest to medical researchers and practitioners. Copyright © 2004 John Wiley & Sons, Ltd.
Modelling neuromotor ratings with floor‐effects
Authors: Gasser Theo , Rousson Valentin
Published: November 2004

Associated movements (AMs) are a classical diagnostic tool to assess differences between normal children and children with some motor dysfunction. This paper presents a methodology to produce age‐ and gender‐dependent reference‐curves for AMs of normal children, for various tasks of a test battery. Data available consist of separate ratings of duration and extent of AMs, which are ordinal quantities with few levels. Other problems are severe age‐ and gender‐dependent floor‐effects (as well as some ceiling‐effects), leaving little information for analysis at older ages. To get a better scale, we combined the two ordinal ratings into one meaningful and quasi‐continuous quantity referred to as intensity of AMs. In order to solve problems due to floor‐effects, ceiling‐effects and discreteness, we assumed left‐ , right‐ and interval‐censored values, respectively. We considered a censored regression problem and postulated a truncated normal distribution for the non‐censored values (after an appropriate transformation of the data). Using Wei and Tanner's poor man's data augmentation algorithm, together with the technique of linear mixed effects modelling, useful reference‐curves could be produced. In contrast to the cumulative probabilities approach for ordinal data, our methodology allows the calculation of individual age‐ and gender‐standardized values, which puts us in a position to investigate numerous scientific questions. Copyright © 2004 John Wiley & Sons, Ltd.
Using the area under the curve to reduce measurement error in predicting young adult blood pressure from childhood measures
Authors: Cook Nancy R. , Rosner Bernard A. , Chen Wei , Srinivasan Sathanur R. , Berenson Gerald S.
Published: November 2004

Tracking correlations of blood pressure, particularly childhood measures, may be attenuated by within‐person variability. Combining multiple measurements can reduce this error substantially. The area under the curve (AUC) computed from longitudinal growth curve models can be used to improve the prediction of young adult blood pressure from childhood measures. Quadratic random‐effects models over unequally spaced repeated measures were used to compute the area under the curve separately within the age periods 5–14 and 20–34 years in the Bogalusa Heart Study. This method adjusts for the uneven age distribution and captures the underlying or average blood pressure, leading to improved estimates of correlation and risk prediction. Tracking correlations were computed by race and gender, and were approximately 0.6 for systolic, 0.5–0.6 for K4 diastolic, and 0.4–0.6 for K5 diastolic blood pressure. The AUC can also be used to regress young adult blood pressure on childhood blood pressure and childhood and young adult body mass index (BMI). In these data, while childhood blood pressure and young adult BMI were generally directly predictive of young adult blood pressure, childhood BMI was negatively correlated with young adult blood pressure when childhood blood pressure was in the model. In addition, racial differences in young adult blood pressure were reduced, but not eliminated, after controlling for childhood blood pressure, childhood BMI, and young adult BMI, suggesting that other genetic or lifestyle factors contribute to this difference. Copyright © 2004 John Wiley & Sons, Ltd.
Box–Cox transformation of left‐censored data with application to the analysis of coronary artery calcification and pharmacokinetic data
Authors: Han Cong , Kronmal Richard
Published: November 2004

Box–Cox transformation is investigated for regression models for left‐censored data. Examples are provided using coronary calcification data from the Multi‐Ethnic Study of Atherosclerosis and pharmacokinetic data of a nicotine nasal spray. Copyright © 2004 John Wiley & Sons, Ltd.
Conditional mixed models adjusting for non‐ignorable drop‐out with administrative censoring in longitudinal studies
Authors: Li Jingjin , Schluchter Mark D.
Published: November 2004

In this paper, a class of conditional mixed models is proposed to adjust for non‐ignorable drop‐out, while also accommodating unequal follow‐up due to staggered entry and administrative censoring in longitudinal studies. Conditional linear and quadratic models which model subject‐specific slopes as linear or quadratic functions of the time‐to‐drop‐out, as well as pattern mixture models are both special cases of this approach. We illustrate these models and compare them with the usual maximum likelihood approach assuming ignorable drop‐out using data from a multi‐centre randomized clinical trial of renal disease. Simulations under various scenarios where the drop‐out mechanism is ignorable and non‐ignorable are employed to evaluate the performance of these models. Copyright © 2004 John Wiley & Sons, Ltd.