bluuebunny/crossref_metadata_2025 huggingface dataset:
Simple design equations for omnidirectional axis‐displaced dual‐reflector antennas
Authors: Bergmann José R. , Moreira Fernando J. S.
Published: March 2005

This paper considers the use of dual‐reflector antennas for omnidirectional coverage. The reflectors are axially symmetric surfaces generated by axis‐displaced conic sections. By using geometrical optics (GO) principles, simple design equations for the different configurations are established. The simple equations allow an easy identification of the relevant features of the different dual‐reflector configurations. The design parameters are explored to provide compact arrangements suited for use at base stations of point‐to‐multi‐point radio links. The design for maximum efficiency is obtained by employing a combination of GO fields and an aperture method to evaluate the antenna‐radiation patterns. Numerical simulations based on the method of moments (MoM) are presented to illustrate the usefulness and advantages of the proposed dual‐reflector antennas. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 159–163, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20756
24‐line of Brillouin‐Erbium fiber laser utilizing a Fabry–Pérot cavity in L‐band
Authors: Haddud T. A. , Al‐Mansoori M. H. , Zamzuri A. K. , Shaharudin S. , Abdullah M. K. , Mahdi M. A.
Published: March 2005

In this paper, the generation of a multiwavelength laser source from a Brillouin‐Erbium fiber laser in the long wavelength band (L‐band) region is experimentally demonstrated. The proposed laser system utilizes a Fabry–Pérot cavity formed by fiber‐loop mirrors. Twenty‐four lines of Brillouin–Stokes with line spacings of 10 GHz are obtained in the L‐band region. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 165–167, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20758
A 0.18‐μm CMOS CMFB downconversion micromixer with deep N‐well technology for LO‐RF and LO‐IF isolation improvements
Authors: Meng C. C. , Hsu S. K. , Wu T. H. , Huang G. W.
Published: March 2005

CMOS deep N‐well technology can eliminate the physical effects of NMOS transistors and reduce substrate noise and coupling in order to reach the NMOS channel. These properties result in better LO‐IF and LO‐RF isolations in a Gilbert micromixer. Two identical 0.18‐μm CMOS downconversion micromixers (except at the RF input stage) with deep N‐well or without deep N‐well are fabricated in adjacent areas of the same wafer for the purpose of isolation comparison. A −37‐dB LO‐IF and −38‐dB LO‐RF isolation downconversion micromixer with 19‐dB conversion gain and IP1dB = −20 dBm and IIP3 = −13 dBm when RF = 2.4 GHz and LO = 2.25 GHz is demonstrated here using 0.18‐μm‐deep N‐well CMOS technology. On the other hand, a downconversion micromixer without deep N‐well has almost identical power performance but achieves only −20‐dB LO‐IF isolation and −21‐dB LO‐RF isolation. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 168–170, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20759
1H NMR spectroscopy in the diagnosis of Pseudomonas aeruginosa‐induced urinary tract infection
Authors: Gupta Ashish , Dwivedi Mayank , Nagana Gowda G. A. , Ayyagari Archana , Mahdi A. A. , Bhandari M. , Khetrapal C. L.
Published: March 2005

The utility of 1H NMR spectroscopy is suggested and demonstrated for the diagnosis of Pseudomonas aeruginosa in urinary tract infection (UTI). The specific property of P. aeruginosa of metabolizing nicotinic acid to 6‐hydroxynicotinic acid (6‐OHNA) is exploited. The quantity of 6‐OHNA produced correlates well with the viable bacterial count. Other common bacteria causing UTI such as Escherichia coli, Klebsiella pneumonia, Enterobacter aerogenes, Acinetobacter baumanii, Proteus mirabilis, Citrobacter frundii, Enterococcus faecalis, Streptococcus gp B and Staphylococcus aureus do not metabolize nicotinic acid under similar conditions. The method provides a single‐step documentation of P. aeruginosa qualitatively as well as quantitatively. The NMR method is demonstrated on urine samples from 30 patients with UTI caused by P. aeruginosa. Copyright © 2005 John Wiley & Sons, Ltd.
Global protein expression analysis in apicomplexan parasites: Current status
Authors: Belli Sabina I. , Walker Robert A. , Flowers Sarah A.
Published: March 2005

Members of the phylum Apicomplexa are important protozoan parasites that cause some of the most serious, and in some cases, deadly diseases in humans and animals. They include species from the genus Plasmodium, Toxoplasma, Eimeria, Neospora, Cryptosporidium, Babesia and Theileria. The medical, veterinary and economic impact of these pathogens on a global scale is enormous. Although chemo‐ and immuno‐prophylactic strategies are available to control some of these parasites, they are inadequate. Currently, there is an urgent need to design new vaccines or chemotherapeutics for apicomplexan diseases. High‐throughput global protein expression analyses using gel or non‐gel based protein separation technologies coupled with mass spectrometry and bioinformatics provide a means to identify new drug and vaccine targets in these pathogens. Protein identification based proteomic projects in apicomplexan parasites is currently underway, with the most significant progress made in the malaria parasite, Plasmodium falciparum. More recently, preliminary two‐dimensional gel electrophoresis maps of Toxoplasma gondii and Neospora caninum tachyzoites and Eimeria tenella sporozoites, have been produced, as well as for micronemes in E. tenella. In this review, the status of proteomics in the analysis of global protein expression in apicomplexan parasites will be compared and the challenges associated with these investigations discussed.
Multiscale modeling of viscoelastic properties of polymer nanocomposites
Authors: Borodin Oleg , Bedrov Dmitry , Smith Grant D. , Nairn John , Bardenhagen Scott
Published: March 2005

A methodology for simple multiscale modeling of mechanical properties of polymer nanocomposites has been developed. This methodology consists of three steps: (1) obtaining from molecular dynamics simulations the viscoelastic properties of the bulklike polymer and approximating the position‐dependent shear modulus of the interfacial polymer on the basis of the polymer‐bead mean‐square displacements as a function of the distance from the nanoparticle surface, (2) using bulk‐ and interfacial‐polymer properties obtained from molecular dynamics simulations and performing stress–relaxation simulations of the nanocomposites with material‐point‐method simulations to extract the nanocomposite viscoelastic properties, and (3) performing direct validation of the average composite viscoelastic properties obtained from material‐point‐method simulations with those obtained from the molecular dynamics simulations of the nanocomposites. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1005‐1013, 2005
Quantitative structure property relationship models for the prediction of liquid heat capacity
Authors: Yao Xiaojun , Fan Botao , Doucet J. P. , Panaye A. , Liu Mancang , Zhang Ruisheng , Zhang Xiaoyun , Hu Zhide
Published: March 2005

Quantitative Structure‐Property Relationship (QSPR) models based on molecular descriptors derived from molecular structures have been developed for the prediction of liquid heat capacity at 25 °C using a diverse set of 871 organic compounds. The molecular descriptors used to represent molecular structures include constitutional and topological indices and quantum chemical parameters. Forward stepwise regression and radial basis function neural networks (RBFNNs) were used to construct the QSPR models. The root mean square errors in liquid heat capacity predictions for the training, test and overall data sets are 16.857, 18.744 and 17.141 heat capacity units, respectively. The prediction results are in agreement with the experimental values, but the RBFNN model seems to be better than stepwise regression method.
Bioconcentration potential predictions based on molecular attributes – an early warning approach for chemicals found in humans, birds, fish and wildlife
Authors: Dimitrov Sabcho D. , Dimitrova Nadezhda C. , Walker John D. , Veith Gilman D. , Mekenyan Ovanes G.
Published: March 2005

The bioaccumulation potential of chemicals is used to indicate when chemicals are likely to contaminate fish, birds and other wildlife, and humans. Together with knowledge of the persistence of chemicals, the bioaccumulation potential is useful in setting priorities for hazard identification as well as environmental monitoring. Because the measurement of the bioaccumulation potential is costly, developing reliable estimates of this important indicator directly from chemical structure has long been a goal of Quantitative Structure Activity Relationship (QSAR) practitioners. Many previous models for predicting bioconcentration factors (BCF) for organic chemicals have been based on linear and bilinear relationships between log(BCF) and octanol‐water partition coefficient (log(Kow)) , some of which also included other structural parameters such as structural correction factors or molecular connectivity indices, Fujita's characters, etc. Most of these BCF models have been derived for predicting passive diffusion of chemicals with log. octanol‐water partition coefficients log(Kow) <7. Most previous models showed large discrepancy for large number of chemicals (predominantly highly lipophilic) found in humans and fish. The effect of steric molecular attributes on predicting BCF was studied using 694 chemicals with available experimental BCF and Kowvalues. It was found that maximum cross sectional diameters and conformational flexibility of chemicals affect significantly bioconcentration and could be used to explain identification of certain highly hydrophobic chemicals in humans and fish.
Modeling mode of action of industrial chemicals: Application using chemicals on Canada's Domestic Substances List (DSL)
Authors: Dimitrov S. , Koleva Y. , Lewis M. , Breton R. , Veith G. , Mekenyan O.
Published: March 2005

Traditionally quantitative structure activity relationships (QSARs) are derived on the assumption that similar chemicals should behave in a toxicologically similar manner. The development of mechanistic models for acute toxicity requires the chemical classification to be based on similar mode of toxic action. Currently, the classification approaches used to predict the mode of toxic action are predominantly based on chemical fragments and, to a lesser extent, on their electronic properties. The discrete nature of the fragment‐based approach, however, yields a classification that does not consider the electronic features of the entire chemical that has “continuous character”. The present study is based on the assumption that chemicals with the same mode of toxic action should possess commonality in their steric and electronic structure. The COmmon REactivity PAtterns (COREPA) approach has been applied to define the global physical properties and quantum‐chemical descriptors best clustering chemicals according to their behavioural mode of action (MOA). The derived COREPA models for each mode were translated into decision trees and applied to screen the organic chemicals on Canada's Domestic Substances List (DSL) for their mode of toxic action.
The Importance of Being Earnest: Validation is the Absolute Essential for Successful Application and Interpretation of QSPR Models
Authors: Tropsha Alexander , Gramatica Paola , Gombar Vijay K.
Published: March 2005

This paper emphasizes the importance of rigorous validation as a crucial, integral component of Quantitative Structure Property Relationship (QSPR) model development. We consider some examples of published QSPR models, which in spite of their high fitted accuracy for the training sets and apparent mechanistic appeal, fail rigorous validation tests, and, thus, may lack practical utility as reliable screening tools. We present a set of simple guidelines for developing validated and predictive QSPR models. To this end, we discuss several validation strategies including (1) randomization of the modelled property, also called Y‐scrambling, (2) multiple leave‐many‐out cross‐validations, and (3) external validation using rational division of a dataset into training and test sets. We also highlight the need to establish the domain of model applicability in the chemical space to flag molecules for which predictions may be unreliable, and discuss some algorithms that can be used for this purpose. We advocate the broad use of these guidelines in the development of predictive QSPR models.
QSAR Models of the in vitro Estrogen Activity of Bisphenol A Analogs
Authors: Coleman Kelly P. , Toscano William A. , Wiese Thomas E.
Published: March 2005

Bisphenol A is a monomer constituent of epoxy and polycarbonate resins used in consumer products. Many studies have shown that bisphenol A is a weak estrogen receptor agonist with endocrine disrupting potential in exposed organisms. Presented here is a series of quantitative structure‐activity relationship models to describe the in vitro hormone activity (estrogen receptor binding, reporter gene induction, and cell proliferation) of bisphenol A and 24 of its analogs. The hormone activity ranged over four orders of magnitude, with bisphenol A displaying intermediate activity. Comparative molecular field analysis, comparative molecular similarity indices, and hologram quantitative structure activity models were generated using SYBYL 6.8. Bisphenols with optimal estrogen activity contained two unencumbered phenolic groups in the para orientation, and multiple alkyl substituents extending from the carbon linking phenolic rings. Bisphenols with methyl group hydrogens replaced by halogens also produced strong estrogenic analogs. These studies suggest that it may be possible to use such structure activities to develop bisphenols that are useful monomers with reduced hormone activity.
From Science to Innovation and From Data to Knowledge: eScience in the Dutch Polymer Institute's High‐Throughput Experimentation Cluster
Authors: Adams Nico , Schubert Ulrich S.
Published: March 2005

Modern materials research increasingly relies on the use of combinatorial and high‐throughput synthesis and screening methods in order to shorten product development times and to maintain filled product pipelines. In order to derive maximum benefit from such technologies, an informatics infrastructure, which supports the experimental work, is indispensable. This paper discusses the efforts made at the Dutch Polymer Institute (DPI) to develop such a system. A detailed requirements and workflow analysis is presented, together with the solution implemented at the DPI. In our approach, we have focussed on the use of existing and proven enterprise technologies, based on open standards, such as JAVA, J2EE, XML and SQL. This allows the rapid development of interfaces between applications as required.
Integrated Informatics in Life and Materials Sciences: An Oxymoron?
Authors: Gilardoni François , Curcin Vasa , Karunanayake Kanishka , Norgaard Jonas , Guo Yike
Published: March 2005

The pharmaceutical and chemical industries are facing significant internal and external pressure to boost the experimental efficiency and effectiveness by cutting the direct research costs and reducing the time to market for new sustainable products. Other key issues to secure a competitive return on investment are to enable the rescue of stalled product development projects, abort failing projects early, enhance collaborative multidisciplinary ventures, and ensure an effectual risk management and cost savings through safety testing and failure analysis. Typically, modern organizations rely on a variety of informatics solutions from well‐established software vendors. These typically operate on different platforms and are controlled by different management systems using different data types and proprietary formats. Maintaining, integrating, updating and monitoring these powerful, but disparate, ensembles of tools, are an intricate and expensive operation. We present the concept of the Enterprise Discovery Planning (EDP) software platform design to facilitate the optimization of discovery activities at an enterprise level. We also briefly present how Inforsense addresses these issues.
Effect of the Genetic Algorithm Parameters on the Optimisation of Heterogeneous Catalysts
Authors: Pereira Silvia R. M. , Clerc Frederic , Farrusseng David , van der Waal Jan C. , Maschmeyer Thomas , Mirodatos Claude
Published: March 2005

A study of the effect of Genetic Algorithm (GA) configurations on the performance of heterogeneous catalyst optimisation is reported. The GA optimisation procedure is validated on real case studies. Experimental data to construct the benchmarks were collected by means of High‐Throughput Experimentation (HTE) on CO oxidation (COox) and selective CO oxidation (Selox) reactions. For the search space mapping, 189 catalysts were tested for the two reaction conditions at different temperatures, resulting in 1134 test reactions from which two benchmarks were derived. For the algorithm configuration, an in‐house‐implemented GA platform was used enabling a large variety of operator combinations. Because of the typical limitations in the number of parallel experiments that can be carried out in heterogeneous catalysis, the effects of the population size on the robustness and convergence speed were investigated. From this study, general considerations about the algorithm settings (crossover, selection and mutation) to use for the optimisation of heterogeneous catalysts are addressed.
Application of Data Mining and Evolutionary Optimization in Catalyst Discovery and High‐Throughput Experimentation – Techniques, Strategies, and Software
Authors: Ohrenberg Arne , von Törne Christian , Schuppert Andreas , Knab Bernhard
Published: March 2005

Data‐mining and evolutionary optimization techniques are powerful tools to improve the efficiency of high‐throughput experimentation (HTE) to discover new materials, drugs, or catalysts.
Robust Material Design: A New Workflow for High‐Throughput Experimentation and Analysis
Authors: Nicolaides David
Published: March 2005

The analysis of highly replicated experiment sets is described. These experiments are often performed as part of validating high‐throughput experimentation (HTE) apparatus. Their analysis has been greatly simplified by the application of traditional regression methods in combination with the development of novel multi‐objective optimisers. These methods allow the analysis to treat the problem of “robust design” inherent in materials and product development. Robust design tries to ensure that a material performs to a specification in spite of manufacturing or usage conditions which are not under the control of the designer. This problem is especially amenable to solution by a method combining HTE and analysis.
Split‐Plot Experimental Designs for Combinatorial and High‐Throughput Experimentation
Authors: Castillo Flor A. , Sweeney Jeff , Margl Peter , Zirk Wayne
Published: March 2005

In the last few years, high‐throughput reactors have small received significant attention due to the potential they offer for fast material development. While many experimental design techniques are proposed, statistical issues related to experimentation in this type of equipment are emerging. One of the experimental design techniques needed is the split‐plot approach, given the randomization restrictions imposed by the equipment. This paper presents the use of split‐plot experimental designs in a high‐throughput reactor. We discuss the unique error structure of these designs and the special statistical analysis that considers two different types of errors. A case study in the Dow Chemical Company is presented. The main advantage of the split‐plot approach related to high throughput is that reactor‐well utilization can be maximized, while randomization restrictions can be addressed correctly and simultaneously. The results obtained indicate the success of this strategy in maximizing the chance of detecting a lead and making the right conclusions, which is of key importance given the speed of data generation of high‐throughput reactors.
Theory of Monte Carlo simulations of the magnetic circular dichroism spectra of alkali metal/rare gas systems
Authors: Kenney John W. , Boatz Jerry A. , Terrill Vosbein Heidi A.
Published: March 2005

The history of magnetic circular dichroism (MCD) spectroscopy in the study of alkali metal/rare gas (M/Rg) cryogenic systems is reviewed in the context of developing a better understanding of alkali metal/hydrogen systems of current interest to the U.S. Air Force as enhanced‐performance cryogenic rocket propellants. A new theory for simulating the MCD spectra of M/Rg systems is presented together with a careful discussion of the theory's implicit and explicit approximations and their implications. This theory uses a classical Monte Carlo (MC) simulation scheme to model the perturbing effects of the Rg environment on the 2S → 2P MCD‐active transition of the M atom. The theory sets up the MC–MCD simulation as a 6 × 6 matrix eigenvalue/eigenvector problem in the 2P manifold in which are included the effects of M–Rg interactions, metal atom spin‐orbit coupling in the 2P manifold, magnetic Zeeman perturbations of the 2S and 2P manifolds, Boltzmann temperature factors, and electric dipole transition moment integrals for left circularly polarized (LCP) and right circularly polarized (RCP) light. The theory may be applied to any type of trapping site of the host M in the guest Rg matrix; a single atom substitutional metal atom trapping site (one host Rg atom is replaced by one guest M atom) is modeled in this study for M = Na and Rg = Ar. Two temperature factors are used in these simulations; a lattice temperature to model the mobility of the Rg lattice and a magnetic temperature to model Boltzmann factors in the 2S ground manifold. The 6 × 6 eigenvalue/eigenvector problem is solved for a number of randomly generated and suitably averaged Rg configurations to yield the simulated MC‐MCD spectrum for the single substitutional Na/Ar system. The MC–MCD simulations of Na/Ar give the characteristic triplet MCD spectrum with the correct Boltzmann temperature dependence. The simulated MC–MCD spectrum correctly inverts when the direction of the applied magnetic field is reversed. Addition of the LCP and RCP absorbances gives rise to a characteristic 2S → 2P triplet absorption feature. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Kernel energy method illustrated with peptides
Authors: Huang Lulu , Massa Lou , Karle Jerome
Published: March 2005

We describe a kernel energy method (KEM) for applying quantum crystallography to large molecules, with an emphasis on the calculation of the molecular energy of peptides. The computational difficulty of representing the system increases only modestly with the number of atoms. The calculations are carried out on modern parallel supercomputers. By adopting the approximation that a full biological molecule can be represented by smaller “kernels” of atoms, the calculations are greatly simplified. Moreover, collections of kernels are, from a computational point of view, well suited for parallel computation. The result is a modest increase in computational time as the number of atoms increases, while retaining the ab initio character of the calculations. We describe a test of our method, and establish its accuracy using 15 different peptides of biological interest. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Are water–aromatic complexes always stabilized due to π–H interactions? LMP2 study
Authors: Reyes Abraham , Fomina Lioudmila , Rumsh Lev , Fomine Serguei
Published: March 2005

Eight complexes of various aromatic molecules with water have been studied theoretically at the local Møller–Plesset 2nd order theory (LMP2)/aug‐cc‐pVTZ(‐f)//LMP2/6‐31+G* level of theory. Two types of complexes can be formed, depending on the electronic structure of aromatic molecules. Donor hydrocarbons form A‐type complexes, while aromatics bearing electron‐withdrawing substituents form B‐type complexes. A‐type complexes are stabilized due to π–H interactions with the OH bond pointing to the aromatic molecule plane, while B‐type complexes have geometry with the oxygen atom pointing to the aromatic molecule plane stabilized by the interaction of highest occupied molecular orbital (HOMO) of water molecule with π* orbitals of the aromatics. It has been found that a (HOMO–lowest unoccupied molecular orbital (LUMO)/2 value of aromatic molecule, which can be called “molecular electronegativity,” is useful to predict the type of complex formed by aromatic molecule and water. Aromatic hydrocarbons with “molecular electronegativity” of <0.15 tend to form A‐type complexes, while aromatic molecules with “molecular electronegativity” of <0.15 a.u. form B‐type complexes. The binding energy of water–aromatic complexes undergoes a minimum in the area of switching from A‐type to B type complexes, which can be rationalize in terms of frontier orbital interactions. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Optimizing dam release rules to meet environmental flow targets
Authors: Harman Ciaran , Stewardson Michael
Published: March 2005

Linking environmental flow dam release rules to environmental variables has potential to link the flow variability of a regulated stream to the environmental forces acting on the catchment. A technique is developed to examine a range of release rules related to gauged tributary inflows and optimize these with respect to total water release volumes and other criteria. A model is created consisting of three parts: (1) a Dam Release Event Generator, which generates dam releases according to a set of rules, (2) a simple routing model using linear transforms and derived time‐series for ungauged tributary inflows, (3) an algorithm to analyse the output time‐series and produce statistics on the environmental flows. This model is run for a range of rule parameters within a parameter space. The results showed that multiple strategies might be capable of achieving the required targets but that some of these may be more robust in the face of climate variability than others. Significant water savings can result from the use of the technique. However, the results also highlight the limitations of the way environmental flows are currently stipulated and point towards a new generation of environmental flows. The technique is applied to environmental flow targets in the Thomson River catchment, Victoria, Australia. Copyright © 2005 John Wiley & Sons, Ltd.
Variability in the development, persistence and breakdown of thermal, oxygen and salt stratification on regulated rivers of southeastern Australia
Authors: Turner Lisa , Erskine Wayne D.
Published: March 2005

Detailed depth profiles of temperature, dissolved oxygen, salinity and oxidation‐reduction potential (ORP) at many sites over two to four years were made on three highly regulated rivers in southeastern Australia which have experienced large‐scale streamflow reductions for urban water supply (Nepean River) or urban, stock and domestic supplies (Glenelg River) or hydropower generation (Snowy River). Well‐developed oxygen stratification was detected on all rivers in summer and was associated with thermal stratification. Hypoxia or anoxia was often measured below the oxycline and reducing conditions (ORP up to −200 mv) were usually associated with such anoxia. Saline groundwater inflows were detected on both the Nepean and Glenelg rivers and produced salt stratification in addition to thermal and oxygen stratification. Density differences of up to 3.7 kg/m3 were determined across the oxycline with no salt stratification, but increased to 14.9 kg/m3 when salt stratification occurred in the upper estuary of the Snowy River. Sediment‐bound phosphorus was released under reducing conditions with order of magnitude increases in total phosphorus concentrations being measured below the oxycline. Similarly, increases of at least 50% and up to one order of magnitude in dissolved iron, aluminium, manganese and/or sulphur were also measured when anoxic and reducing conditions were recorded below the oxycline. Water depth exerted a significant control on thermocline development with depths of at least 5 m, but usually 6 m, being required for thermal stratification in pools. Deep natural scour pools stratify on all three rivers but dredging of weir pools on the Nepean River has increased the extent of stratification. Anoxic and/or hypoxic conditions below the oxycline greatly reduce the amount of aquatic habitat available for aerobic organisms, especially benthic fish. Winds of 50 km/h generated sufficient shear to completely overturn the stratified Cobbitty weir pool on the Nepean River and winds of 28–44 km/h completely mixed epilimnetic waters in Rocklands Reservoir, breaking down temporary thermoclines. Trial environmental streamflows of 21.7 to 40.7 m3/s generated epilimnetic flow velocities that caused sufficient turbulence to effect mixing by gradual entrainment on the Nepean River. However, these flows would need to persist for more than 5 days to break down stratification in the deepest pools. Stratification rapidly redeveloped, even on the recession of the releases. Copyright © 2005 John Wiley & Sons, Ltd.
The role of flooding in morphological changes in the regulated Lower Ord River in tropical northwestern Australia
Authors: Cluett Lisa
Published: March 2005

The discharge of the Lower Ord River has been regulated since 1972 when a second dam was built on this major river system. This previously ephemeral river, punctuated by peak wet season flows, is now characterized by permanent, regulated flows all year, and complex adjustments to the downstream channel morphology are evident. Geographic Information System techniques, combined with field surveys, reveal a series of interrelated adjustments in response to recent flooding. These include sedimentation, channel narrowing and vegetation encroachment, all of which have implications for sustainable management and are issues that have been managed by flushing flows in other rivers. The largest flood events since regulation occurred some 27 years after dam construction during consecutive wet seasons. These events have prompted an examination of the potential to ‚flush’︁ the post‐regulation Lower Ord channel to modify some of the channel changes that occurred in response to dam construction. A detailed geomorphic investigation of the Lower Ord river showed that that some of the features formed under low flows have been eradicated (partly or completely) by these large flood events, while others have withstood them. The modification of changes since dam construction varies according to a range of factors including reach position, extent of vegetation cover and local morphological variation. It is clear, however, that features not removed during floods may be considered quasi‐permanent, and therefore are likely to play an important role in the evolution of this regulated river. Copyright © 2005 John Wiley & Sons, Ltd.
Spatial variability and temporal change of water discharge and sediment flux in the Lower Jinsha tributary: impact of environmental changes
Authors: LU X. X.
Published: March 2005

Analysis of water discharge and sediment flux data as measured in the Longchuanjiang Basin in the Lower Jinsha tributary over the past few decades has been undertaken. The results of this study indicate that the lower reaches of the Longchuanjiang River produce relatively less runoff but higher sediment loads than the upper reaches. This can be attributed to the differences in climate, the dissected terrain and the sparse vegetation cover of the downstream river. Temporal series analysis suggests a significant increase in sediment flux, notably in the lower reaches of the river. The available data suggest the increasing sediment flux is a result of climate variations and a series of human activities such as land‐use changes, mainly through deforestation and agricultural expansion. Other activities, such as road construction, urban expansion, building‐material excavation and large‐scale terrace construction and afforestation, have also contributed to the significant increase in the sediment flux. However, the Longchuanjiang Basin as a whole has a low sediment yield (< 1000 t km−2 a−1), despite severe soil erosion in the catchment. This is a result of sediment deposition in the numerous reservoirs, constructed since the 1950s. Runoff in the dry season has also significantly declined due to increasing water consumption. These profound changes in the hydrological regime will have significant implications for effective soil erosion and water management. Further studies in the region are necessary to address the impact of these human activities on hydro‐geomorphological processes and, particularly, water discharge and sediment flux. Copyright © 2005 John Wiley & Sons, Ltd.
Linking scales of flow variability to lotic ecosystem structure and function
Authors: Biggs Barry J. F. , Nikora Vladimir I. , Snelder Ton H.
Published: March 2005

Obtaining a better knowledge of how flow variability affects lotic biota is of considerable importance to stream and river management. We contend that processes at different hierarchical levels of organization in lotic ecosystems are sensitive to variation in flow at related hierarchical temporal scales. Ecosystem disturbance caused by large‐scale events (i.e. infrequent, but high magnitude flow events with a recurrence interval of years to many days) tend to determine high‐level characteristics of ecosystem structure (e.g. determining species pools, periphyton versus macrophyte dominance) and function (e.g. balance between auto‐ and heterotrophy). The high‐level ecosystem characteristics then set the stage for processes that are influenced by flow variation that occurs at smaller temporal scale (i.e. minutes to milliseconds) such as colonization, biotic interactions and mass transfer enhancement of production. We contend that large‐scale temporal events predominantly affect lotic ecosystems through physical drag processes (‘drag‐disturbance’), whereas small‐scale flow variations affect ecosystems through mass‐transfer processes (including invertebrate and fish food‐uptake). Drag‐disturbance and mass‐transfer related processes mark the opposite ends of a continuum of flow variability controlled processes, with moderate temporal scale flow variability events affecting ecosystems through both drag‐disturbance and mass‐transfer processes in similar proportions. Flow variability, and associated effects on ecosystems, across these scales is discussed with reference to New Zealand rivers. We suggest that these concepts can be integrated across the full range of temporal scales based on a spectrum of velocity variations. This may provide a unifying conceptual model for how the structure and functioning of lotic ecosystems are linked to flow variability. Copyright © 2005 John Wiley & Sons, Ltd.
This is who I am: Experiences of Native American students
Authors: Lowe (Navajo) Shelly C.
Published: March 2005

This chapter shares the experiences of some Native American students in mainstream education and provides recommendations for student affairs professionals working with Native American students.
Perspectives of American Indian nation parents and leaders
Authors: Austin (Navajo) Raymond D.
Published: March 2005

The author offers insights into perceptions and expectations that tribal leaders and Native American parents have of higher education.
Chemical composition and mass closure for fine and coarse aerosols at a kerbside in Budapest, Hungary, in spring 2002
Authors: Maenhaut Willy , Raes Nico , Chi Xuguang , Cafmeyer Jan , Wang Wan , Salma Imre
Published: March 2005

A comprehensive chemical aerosol characterization was carried out at a kerbside in downtown Budapest in spring 2002. Several filter samplers were deployed in parallel for day and night collections, and a total of 23 parallel collections were made. All samples were analysed for the particulate mass (PM) by weighing. Depending on the sampler type and/or collection substrate, further analyses were performed for up to 46 elements by a combination of particle‐induced x‐ray emission (PIXE) spectrometry and instrumental neutron activation analysis (INAA), for major anions and cations by ion chromatography and for organic carbon and elemental carbon by a thermal–optical transmission technique. Some of the elements measured could clearly be associated with traffic‐related sources, e.g. Cu and Sb were attributed to emissions from brake linings. Aerosol chemical mass closure calculations were made for the separate fine (<2 µm) and coarse (2–10 µm) size fractions and also for the PM10 aerosol. For reconstituting the gravimetric PM, eight aerosol types were considered, and three aerosol types were deduced from the PIXE/INAA elemental data set. Organic matter and elemental carbon were the dominant aerosol types in the fine fraction; they explained on average 43 and 21%, respectively, of the fine PM. The coarse PM consisted mainly of crustal matter (49%) and organic matter (30%). The large contribution from crustal matter (road dust) to the coarse fraction is consistent with other data from kerbside sites in Europe. Copyright © 2005 John Wiley & Sons, Ltd.
Differential PIXE measurements for the stratigraphic analysis of the painting Madonna dei fusi by Leonardo da Vinci
Authors: Grassi N. , Migliori A. , Mandò P. A. , Calvo del Castillo H.
Published: March 2005

Traditional PIXE does not provide information about the layered structure that is characteristic of wood and canvas paintings. In such cases, a solution to discriminate the depth sequence of elements within the analysed sample is to use differential PIXE, i.e. by measuring on the same spot with different beam energies. At the Florence accelerator, laboratory differential PIXE measurements were performed on the wood painting Madonna dei fusi (ex‐Redford version, 1501) by Leonardo da Vinci, in the framework of an extensive project aimed at discovering the ‘secrets’ of the painting and drawing techniques of the artist. The analysis allowed us to characterize the pigments and the substrate composition. Copyright © 2005 John Wiley & Sons, Ltd.
PIXE analysis of atmospheric aerosols in Mexico City
Authors: Miranda J. , Barrera V. A. , Espinosa A. A. , Galindo O. S. , Meinguer J.
Published: March 2005

Samples of atmospheric aerosols were collected at three sites in the metropolitan area of Mexico City and analyzed with particle‐induced x‐ray emission (PIXE). Stacked filter units of the Davis design were employed to obtain samples of PM15 (particles with dimensions below 15 µm mean aerodynamic diameter) on polycarbonate filters, divided in two fractions. The study was conducted during the first half of 2002, exposing the filters every 2 days for 24 h, starting at 08:00 h. Analysis of variance of the measured elemental concentrations showed differences in the mean concentrations for several elements at the sampling sites. Cluster and absolute principal component analyses were applied to identify contributing sources, together with their relative contributions to the mass measured with PIXE. It was found that fugitive dusts are usually the main sources in both fractions from all sites. Copyright © 2005 John Wiley & Sons, Ltd.
Characterization of airborne particulate matter in an industrial district near Florence by PIXE and PESA
Authors: Chiari M. , Lucarelli F. , Mazzei F. , Nava S. , Paperetti L. , Prati P. , Valli G. , Vecchi R.
Published: March 2005

The composition of airborne particulate matter in Montelupo Fiorentino (a small town about 20 km west of Florence characterized by the presence of a large number of ceramic and glass factories) was studied by means of continuous and sequential sampling, ion beam analysis (IBA) techniques and statistical methods. The aerosol PM10 fraction was collected on a daily basis for about 9 months (September 2002–June 2003). To investigate the elemental size distribution, for a shorter period (about 3 weeks) we collected PM10, PM2.5 and PM1 simultaneously. A continuous streaker sampler was also used, which allows the study of the aerosol composition with 2 h time resolution. Mass concentrations were obtained using an analytical balance. The elemental analysis was performed at the INFN accelerator laboratory at the Physics Department of Florence University by particle‐induced x‐ray emission and particle elastic scattering analysis (the latter implemented for this campaign). The use of the two techniques allowed a complete reconstruction of the gravimetric mass. An absolute principal component analysis showed industrial sources to be, on average, the main contributors to PM10 mass; however, the weight of the ‘soil’ source (connected to local soil re‐suspension and to long‐range Saharan transport episodes) becomes dominant during some of the days when the 50 µg m−3 limit is exceeded. Copyright © 2005 John Wiley & Sons, Ltd.
Developing an operational reference framework for fisheries management on the basis of a two-dimensional index of ecosystem impact
Authors: Tudela Sergi , Coll Marta , Palomera Isabel
Published: March 2005

A composite quantitative index for the percentage of primary production required to sustain fisheries and the average trophic level of catch (%PPR–TLc) was employed to develop ecosystem-based reference functions suitable for fisheries management. Established ecosystem models, characterized by pairs of %PPR–TLc, were classified as either sustainably exploited or ecosystem overfished, on the basis of the results of factorial correspondence analysis applied to selected ecological indices, and on information from various sources. Canonical discriminant analysis of these pairs was applied to establish the discriminant function to separate the two exploitation classes. Next, reference functions related to different probabilities of ecosystem overfishing were developed to obtain an operational framework for ecosystem-based fisheries management. Values of ecosystem-based maximum sustainable catches associated with different probabilities of belonging to a sustainable situation were calculated. Overall, results show that most current fishing scenarios entail high risks of ecosystem overfishing.
Playing with fire: an unexpected collaboration
Authors: ALLEN J. ANTHONY
Published: March 2005

Working with dancers to generate musical material has been the interest of many composers since such technologies became available. My work focuses on a particular kind of dance – a fire dancer – to generate sonic material. Working with a fire dancer in a collaborative environment creates a unique set of difficulties with rewarding outcomes.
Collective composition: the case of Edison Studio
Authors: CIPRIANI ALESSANDRO , CIARDI FABIO CIFARIELLO , CECCARELLI LUIGI , CARDI MAURO
Published: March 2005

This article describes the collective experiences of the four composers at Edison Studio, who have recently been working on the soundtracks for two silent movies – four artists involved in the same discipline, working with the same skills and in the same roles. It describes their composition methods, ways in which problems are resolved, the new awareness and understanding they have acquired and the results of work created out of a re-evaluation of individual ways of operating, that seeks to bring together and strengthen the common ground between them.
The Lucid Dream Ensemble: a laboratory of discovery in the age of convergence
Authors: MOOREFIELD VIRGIL , WEETER JEFFREY
Published: March 2005

This paper describes the formation, creations and performances of a digital arts performing ensemble. It considers issues of collaboration across media, especially in the context of composed audio-visual improvisation (comprovisation). By contextualising our creative work within the wider discourse of both the practice and aesthetics of contemporary intermedia, we seek to enhance the potential relevancy of the article's main focus to readers.

The story of the Lucid Dream Ensemble is one of contemporary creative activity in the realm of digital arts. It exists in a university setting, and its purpose is educational as well as artistic. Founded at Northwestern University in Evanston, Illinois in 2002, the ensemble seeks to foster collaboration across auditory and visual boundaries. The group is made up of audio-visual performers who control laptop computers in real-time by various interactive means. Its canvas is a surround-sound set-up, as well as three projectors. The ensemble seeks a true integration of video and audio, as expressed in the creation of audio-visual artefacts aimed at providing an immersive experience. The group has progressed from presenting unrelated audio and video, to integrating the process of creation of sound and image, to collecting audio and video as a group and processing them collaboratively.
The Meta-Orchestra: research by practice in group multi-disciplinary electronic arts
Authors: HARRIS YOLANDE
Published: March 2005

Group multi-disciplinary projects face difficult challenges in social collaboration, diverse technologies and aesthetic grounds. Combining sound, image and space into a sufficiently malleable set of materials for creation is a complex task. As such projects lack a common ground from which to start, an experimental, practical approach is suggested, with a non-hierarchical, informal group structure. The Meta-Orchestra project, tackling these problems since 2000, re-engaged with the issues in a fourth meeting in Maastricht in 2004. This paper lays out the context of multi-disciplinary work, influenced by developments in computer technologies, by outlining the changed roles of the orchestra, the score and audio-visual theories. The Meta-Orchestra is described against a theoretical frame of social, technical and aesthetic considerations. Although the project will not be forced into this framework, descriptions of the palette, the strategies to create common grounds, the areas opened up by wireless network technologies, aesthetic issues of layering sounds and images, and the development of a central score system, illustrate the layered complexities of the Meta-Orchestra.
Alternative venues for computer music: SoundGallery_Living Room_ARTSHIP
Authors: SCHEDEL MARGARET ANNE
Published: March 2005

The audience for contemporary classical music is small – the audience for computer music is even smaller. Traditional concert halls are failing to generate interest in new instrumental music, much less computer music, while museums are having much more success with new art, including art with a technological component. By marketing our music to art galleries and museums, we can reach an audience predisposed to accept the new and unusual in artistic expression. Presenting the works of music outside a traditional proscenium setting also helps shatter any a priori definitions of ‘music’ audiences may hold. Using the term ‘Sound Art’ instead of ‘music’ may also help to free people struggling to appreciate unfamiliar sounds.
A Latent State-Trait Analysis of Implicit and Explicit Personality Measures
Authors: Schmukle Stefan C. , Egloff Boris
Published: March 2005

Abstract. Explicit personality measures assess introspectively accessible self-descriptions. In contrast, implicit personality measures assess introspectively inaccessible processes that operate outside awareness. However, for both kinds of trait measures, the effect of the situation in which the assessment takes place should be as small as possible. The present study aims at quantifying possible systematic occasion-specific effects on implicit measures (Implicit Association Test) and explicit measures (self-report ratings) of extraversion and anxiety by means of a latent state-trait analysis. This analysis revealed that - as desired for personality assessment - all four measures capture mostly stable interindividual differences. Nevertheless, occasion-specific effects were also observed. These effects were (1) more pronounced for implicit than for explicit measures and (2) more pronounced for anxiety than for extraversion. Implications for the implicit assessment of personality traits are discussed.