bluuebunny/crossref_metadata_2025 huggingface dataset:
On an output‐feedback stabilization problem with uncertainty in the relative degree
Authors: Bartolini Giorgio , Pisano Alessandro , Usai Elio
Published: August 2007

This paper deals with an output‐feedback finite‐time control problem for a class of nonlinear uncertain systems whose relative degree is affected by an uncertain system parameter and is therefore unknown at the stage of control design. We show that an existing second‐order sliding mode control algorithm can address successfully the control task of a finite‐time output‐feedback stabilization when the uncertain relative degree is equal to 1 or 2. We derive constructive tuning rules for the control parameters and show its effectiveness by using computer simulations. Copyright © 2007 John Wiley & Sons, Ltd.
Sediment chemistry and nutrient influx in a hydrologically restored bottomland hardwood forest in Midwestern USA
Authors: Zhang Li , Mitsch William J.
Published: August 2007

Exchanges of total N and C between a river and its floodplain forest have been enhanced by sedimentation processes during flood pulses at a 5‐ha bottomland hardwood forest located at the Olentangy River Wetland Research Park in central Ohio. In the spring of 2000, the forest was hydrologically restored by notching an artificial levee that had separated the Olentangy River and its floodplain forest for 100 years. One‐hundred flat sediment traps (30 cm × 30 cm) were used to collect sediment samples during spring/summer flooding events from 2003 to 2005. Results showed that sediment deposition is determined by the landscape variability during flooding events, Net sediment deposit in the wettest area averaged 134 ± 12 g‐dry wt m−2 in 2003, 127 ± 17 g‐dry wt m−2 in 2004 and 149 ± 23 g‐dry wt m−2 in 2005. Total N and C sedimentation ranged from 0.49 to 0.92 g‐N m−2 and 5.2 to 19.9 g‐C m−2. Fe dominates the sediment chemistry and results show the elemental abundance in the order of Al > Fe > Ca > K > Mg > S > P > Na > Mn > Zn > B > Cu > Mo. A hydrologic pulsing index (HPI) could be used as an indicator for mass changes of energies with hydrologic pulsing events. Restoration of seasonally flooded bottomland forests could stimulate potentially large nutrient and Fe releases, which would eventually lead to an enhanced forest productivity and biodiversity. Copyright © 2007 John Wiley & Sons, Ltd.
Volume Change Measurements of Rice by Environmental Scanning Electron Microscopy and Stereoscopy
Authors: Tang Xiaohu , De Rooij Mario , De Jong Liesbeth
Published: August 2007

The measurement of volume change, which is induced by changing the relative humidity, is performed on rice by using environmental scanning electron microscope (ESEM) and stereoscopy techniques. The typical ΔV%∼RH curve of rice in both sorption and desorption can be categorized into three regions: low, intermediate, and high dependence on relative humidity from low‐ to high‐relative humidity. The volume changes faster for rice samples with lower crystallinity, which is because the amorphous component is easier to absorb moisture than the crystalline component. The volume change behavior in various relative humidity environments is comparable with rice isotherm curve in sorption process though discrepancies exist in desorption, which are thought to be the presence of small pores and microstructure changes at high relative humidity. The volume in the desorption branch is less than that in the sorption branch at the same relative humidity, which can be attributed to the collapse of interior structures, existence of small pores, surface topography loss, and amylose leach. SCANNING 29: 197‐205, 2007. © 2007 Wiley Periodicals, Inc.
A Study on Central Moments of the Histograms from Scanning Electron Microscope Charging Images
Authors: Tan Y. Y. , Sim K. S. , Tso C. P.
Published: August 2007

This paper presents a study on using the statistical parameter, central moment, to describe the properties of the histograms of scanning electron microscope (SEM) images. Various charging effects of SEM images and the corresponding histogram profiles are analyzed. The central moment distributions are used to describe the overview of the histograms of an image. The results show that central moments can be used to quantify and characterize the charging images. In particular, the second moment (variance) and third moment (skewness) can be used to distinguish the differences between charging and noncharging images. SCANNING 29: 211‐218, 2007. © 2007 Wiley Periodicals, Inc.
Urban primary‐grade children think and talk science: Curricular and instructional practices that nurture participation and argumentation
Authors: Varelas Maria , Pappas Christine C. , Kane Justine M. , Arsenault Amy , Hankes Jennifer , Cowan Begoña Marnotes
Published: August 2007

We focus on the concept of matter and explore how young children in urban schools bridge their spontaneous concepts and everyday experiences with scientific concepts introduced to them by children's literature information books and their teacher. The study shows how material artifacts used in a sorting activity became ideational tools—semiotic devices that promoted children's engagement with science and shaped the classroom discourse, thinking, and transactions. “Ambiguous” objects, such as a baggie with air, shaving cream, a baggie of salt that children were asked to sort, encouraged them to debate ideas about states of matter. Children used four ways of reasoning about states of matter: macroscopic properties, prototypes, everyday functions, and process of elimination. Furthermore, children's meaning making was intertwined with various socio‐organizational aspects of inquiry—the ways in which children negotiated their roles within their group and in whole‐class sessions, how they worked with each other, how their ideas were heard by others. We discuss how curricular and instructional approaches that do not lead children to one specific answer or way of thinking become catalysts for the creation of discursive spaces, where children and teacher engage in meaning making in the midst of ambiguity and confusion. © 2007 Wiley Periodicals, Inc. Sci. Ed 92:65–95, 2008
Describing and analyzing learning in action: An empirical study of the importance of misconceptions in learning science
Authors: Hamza Karim M. , Wickman Per‐Olof
Published: August 2007

Although misconceptions in science have been established in interview studies, their role during the learning process is poorly examined. In this paper, we use results from a classroom study to analyze to what extent nonscientific ideas in electrochemistry that students report in interviews enter into their learning in a more authentic setting. We audio‐recorded talk between eight pairs of Swedish upper secondary students during a practical on electrochemical cells. Learning was operationalized on a discursive level as a description of what students do and say when taking part in an activity. This enabled an analysis of how encounters with misconceptions influenced the development of students' reasoning, compared to other encounters during the learning experience. Misconceptions did not constrain the development of students' reasoning. Rather, their reasoning developed in response to the contingencies of the specific situation. When misconceptions were encountered, they appeared as alternatives and questions not actively defended. Sometimes, encounters with these misconceptions were generative of the students' reasoning. The results indicate that demonstrating misconceptions in interviews is not enough to assume that they interfere with learning in other contexts. Educational implications and future lines of research based on these findings and on the methodology applied are discussed. © 2007 Wiley Periodicals, Inc. Sci Ed 92:141–164, 2008
Students' predictions about the sensory properties of chemical compounds: Additive versus emergent frameworks
Authors: Talanquer Vicente
Published: August 2007

We investigated general chemistry students' intuitive ideas about the expected properties of the products of a chemical reaction. In particular, we analyzed college chemistry students' predictions about the color, smell, and taste of the products of chemical reactions represented at the molecular level. The study was designed to explore the extent to which novice learners intuitively use an additive framework to predict the properties of the product, rather than an approach that recognizes the emergent nature of the properties of chemical compounds. To this end, we used a mixed‐methods research approach based on answers to multiple‐choice questions and individual interviews with students enrolled in the first year of an introductory general chemistry course for science and engineering majors. Our results indicate that most students at this level rely on an additive heuristic to predict the properties of chemical compounds, overlooking the possibility of emergent properties resulting from the interaction of the atoms that compose the system. Chemistry instructors and chemical educators thus need to intentionally design learning opportunities for students to recognize and differentiate additive and emergent properties in a variety of contexts. © 2007 Wiley Periodicals, Inc. Sci. Ed 92:96–114, 2008
Creative activity support by discovering effective combinations
Authors: Nishihara Yoko , Sunayama Wataru , Yachida Masahiko
Published: August 2007

Creative activities based on combinations are now being carried on everywhere in the world. Whether or not the creative activity succeeds depends on the combinations used in it. Since there are tremendous numbers of candidate combinations, it is impossible to decide at a glance which should be used. Thus, there must be a method of efficiently discovering combinations which are effective in making creative activity a success. This paper proposes a method of discovering combinations that is effective in supporting creative activity. In the proposed method, the originality of each combination and the novelty perceived by users are estimated from the number of hits on Web pages containing the keywords in question, and the effectiveness of the combinations is judged. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(12): 99–111, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20392
Implementation and evaluation of context‐aware agent framework
Authors: Yamasaki Tomohiro , Cho Kenta , Okamoto Masayuki , Okamoto Yuzo , Hattori Masanori
Published: August 2007

We implemented UPA, a framework for building a context‐aware system which supports a user in the ubiquitous environment. Using this framework facilitates the maintaining of sensor information acquired from various devices, user tastes, and context as action histories, and to follow changes of user tastes and context by acquiring a feedback whether a user was actually provided with suitable content. In the research reported in this paper, we evaluated UPA by using an application built with UPA. We confirmed that the cost of system building by developers is greatly reduced, and that UPA achieves the realistic performance as a framework for building a context‐aware system. We also investigated bottlenecks of the application and obtained insights about the improvement of UPA. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(12): 86–98, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20623
Topic‐based language models using Dirichlet Mixtures
Authors: Sadamitsu Kugatsu , Mishina Takuya , Yamamoto Mikio
Published: August 2007

We propose a generative text model using Dirichlet Mixtures as a distribution for parameters of a multinomial distribution, whose compound distribution is Polya Mixtures, and show that the model exhibits high performance in application to statistical language models. In this paper, we discuss some methods for estimating parameters of Dirichlet Mixtures and for estimating the expectation values of the a posteriori distribution needed for adaptation, and then compare them with two previous text models. The first conventional model is the Mixture of Unigrams, which is often used for incorporating topics into statistical language models. The second one is LDA (Latent Dirichlet Allocation), a typical generative text model. In an experiment using document probabilities and dynamic adaptation of n‐gram models for newspaper articles, we show that the proposed model, in comparison with the two previous models, can achieve a lower perplexity at low mixture numbers. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(12): 76– 85, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20629
Generating facial expressions of another person based on estimation of muscular contraction parameters from face image
Authors: Ahn Seonju , Ozawa Shinji
Published: August 2007

We aim to generate facial expressions of various persons more naturally and without any markers and feature lines. We propose a new approach to estimating muscular contraction parameters for the purpose of generating facial expressions. The muscles of the face are commonly known as the muscles of facial expression. The facial expressions of a human are generated by muscle movements inside the face. If the muscle‐based facial model that Waters proposed is used, facial expressions can be generated by muscular contraction parameters. In this paper, first, the facial surface feature points of the face images are detected by image‐processing methods. Next, the muscular contraction parameters are estimated by the neutral expression and arbitrary expression displacement of the facial model wireframe fitting, based on detected facial surface feature points. Finally, the facial expression is generated by the vertex displacements of an individual facial model based on estimated muscular contraction parameters. Experimental results reveal that our approach can generate various facial expressions of the individual facial model, which corresponds to the facial expression of the actual face image. Additionally, we can generate the facial expressions of another person by using the muscular contraction parameters of that person in an individual facial model. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(12): 66–75, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20647
A geometric method for calibration of internal camera parameters of fish‐eye lenses
Authors: Komagata Hideki , Ishii Ikuo , Takahashi Akira , Wakatsuki Daisuke , Imai Hiroei
Published: August 2007

Fish‐eye cameras (cameras with a fish‐eye lens) have a very wide view angle of about 180° and a great depth of field. Therefore, it is possible to take pictures of broad scenes with a fixed posture, and it is suitable for uses like 3D modeling and surveillance cameras for indoor and outdoor environments. Geometrical and optical calibration of the internal parameters are necessary for improvement of the measuring accuracy in the real world. In this paper, we address the geometrical calibration problem. Some geometrical methods for calibration of the internal camera parameters of fish‐eye cameras force the eye camera into a perspective model that is not applicable in wide views of 180° or more. We propose a calibration method using spherical projection and projection models, which combine the projection function of the fish‐eye lens and geometrical distortion models. Our method can perform calibration quickly and with high accuracy by using patterns of horizontal and vertical parallel lines shown on a liquid crystal display (LCD), which can display such patterns with high accuracy. We show the effectiveness of our method by an experimental evaluation with a fish‐eye camera of orthographic projection type, which obtains high resolution near the edges of the imaging area. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(12): 55–65, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20685
Dependable communication using multiple network paths on fast long‐distance networks
Authors: Kodama Yuetsu , Kudoh Tomohiro , Shimizu Toshiyuki
Published: August 2007

For mission critical jobs in distributed computing, a network with a low packet loss rate and no failures is required. The multiple paths method has been studied as a means to achieve dependable communication with tolerable failures. It recovers from failures on a network using the same packet on another path. Since the speed of a long‐distance network becomes faster, dependable communication that tolerates network latency becomes more important. We built a prototype system of a multiple paths method supporting Gigabit Ethernet speed using GtrcNET‐1, a gigabit network testbed. We evaluated it and confirmed that it can continuously communicate even if a path fails, and it achieved a packet loss rate as low as the product of packet loss rates on both paths. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(12): 46–54, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20807
Power‐aware optimization of CPU and frequency allocation based on fairness of QoS
Authors: Harada Fumiko , Ushio Toshimitsu , Nakamoto Yukikazu
Published: August 2007

In embedded real‐time systems, it is important to reduce energy consumption in order to achieve efficient energy utilization. Many investigations have focused on Quality of Service (QoS) control, which adapts the resource consumption of task execution by adapting the QoS of the tasks. In our past work, fairness of QoS has been focused on in the QoS adaptation control methods we have proposed. In this paper, a CPU clock cycle and frequency allocation problem, whose objectives are to minimize the energy consumption for task execution and to maximize the QoS while guaranteeing fairness of QoS, is formulated as a multiobjective optimization problem. We also propose to obtain a Pareto‐optimal solution of the problem by using the weighted‐sum optimization method. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(12): 37–45, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20819
Acquisition of synonyms using relations in product specification tables
Authors: Seki Tsunehito , Shimada Kazutaka , Endo Tsutomu
Published: August 2007

In this paper, we propose a method for acquisition of synonyms from product specifications. Product specifications are presented in tabular form. We utilize structure information, such as attribute‐value pairs, for the acquisition process. First, we extract target words from attributes in specifications for the acquisition process and then vectorize the words using words in their value field. Next we compress the vector space by using Latent Semantic Indexing (LSI). Finally, we classify the words by using a k‐means method. The k‐means methods have some problems, such as initial clusters in the first step and the number of appropriate clusters. We solve the problems by using domain‐knowledge and statistical information. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(12): 25–36, 2007; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/scj.20827
Image estimation of words based on adjective co‐occurrences
Authors: Shimizu Kouhei , Hagiwara Masafumi
Published: August 2007

In natural language, words convey various impressions such as “kurai (dark)‐akarui (bright)” or “kitanai (dirty)‐utsukushii (beautiful).” Impressions play an important role in inferring the speaker's intentions or feelings. Systems that use natural language to support conceptualization or retrieve information by teaching the computer the impressions of words are growing significantly. Therefore, in this paper, the authors propose a technique for estimating the impressions or images that words convey. The proposed technique consists of two processes: similarity measurement and spatial positioning. Similarity measurement uses the enormous amount of text on the Internet to obtain similarities by measuring the co‐occurrence frequency of words. Co‐occurrence conditions, which are limited to the joint co‐occurrences of adjectives or adjectival nouns, are applied to image estimation. Spatial positioning positions words in space by quantifying the similarities that were obtained according to images. The authors used a simulation of an electrical circuit for quantification. The results of evaluation experiments verified that the proposed system could estimate the images of words with high precision. It was also apparent that the proposed system could estimate the images with sufficient precision even for words that were difficult to analyze because of the insufficient number of samples in an existing corpus, including new words and colloquial words or slang. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(12): 14–24, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20853
Web‐application composition through direct editing of Web documents and multiplexing of information access scenarios
Authors: Fujima Jun , Tanaka Yuzuru
Published: August 2007

In order to support user information retrieval on the Web, a framework is needed in which a user can define various types of data links as necessary by extracting only the necessary components from a Web application and then create a new compound document. This compound document refers to a document that includes services and tools embedded in it. In this research, the authors propose a framework which allows for clipping the structural elements of a Web application and directly manipulating the data linkages using formulas. As a result, the user can clip these components into cells from different Web applications, and then by linking them, create a unique compound document. Moreover, the authors provide a framework for cloning the clipped cells in order to compare the results of various different searches. Furthermore, in this paper the authors describe a method to use a word processing document or spreadsheet as a destination for embedding the clipped components, and function linking for these documents and the clipped cells. As a result, the created custom complex document can be reused and shared more easily. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(12): 1–13, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20861
Estimation of ROC curves based on stably distributed biomarkers subject to measurement error and pooling mixtures
Authors: Vexler Albert , Schisterman Enrique F. , Liu Aiyi
Published: August 2007

Additive measurement errors and pooling design are objectively two different issues, which have been separately and extensively dealt with in the biostatistics literature. However, these topics usually correspond to problems of reconstructing a summand's distribution of the biomarker by the distribution of the convoluted observations. Thus, we associate the two issues into one stated problem. The integrated approach creates an opportunity to investigate new fields, e.g. a subject of pooling errors, issues regarding pooled data affected by measurement errors. To be specific, we consider the stated problem in the context of the receiver operating characteristic (ROC) curves analysis, which is the well‐accepted tool for evaluating the ability of a biomarker to discriminate between two populations. The present paper considers a wide family of biospecimen distributions. In addition, applied assumptions, which are related to distribution functions of biomarkers, are mainly conditioned by the reconstructing problem. We propose and examine maximum likelihood techniques based on the following data: a biomarker with measurement error; pooled samples; and pooled samples with measurement error. The obtained methods are illustrated by applications to real data studies. Published in 2007 by John Wiley & Sons, Ltd.
Kernel estimation of risk surfaces without the need for edge correction
Authors: Hazelton Martin L.
Published: August 2007

Kernel estimates of relative risk surfaces can be used to examine the geographical variation of disease risk. These surfaces can be expressed as ratios of bivariate kernel density estimates constructed from case and control data, but care must be taken to avoid excessive bias at the boundaries of the region under study. It is possible to correct this bias, without the complications of explicit edge correction, through the use of a specific smoothing regimen. Copyright © 2007 John Wiley & Sons, Ltd.
The fit between product market strategy and business model: implications for firm performance
Authors: Zott Christoph , Amit Raphael
Published: August 2007

We examine the fit between a firm's product market strategy and its business model. We develop a formal model in order to analyze the contingent effects of product market strategy and business model choices on firm performance. We investigate a unique, manually collected dataset, and find that novelty‐centered business models—coupled with product market strategies that emphasize differentiation, cost leadership, or early market entry—can enhance firm performance. Our data suggest that business model and product market strategy are complements, not substitutes. Copyright © 2007 John Wiley & Sons, Ltd.
Doing well by doing good—case study: ‘Fair & Lovely’ whitening cream
Authors: Karnani Aneel
Published: August 2007

According to the ‘doing well by doing good’ proposition, firms have a corporate social responsibility to achieve some larger social goals, and can do so without a financial sacrifice. This research note empirically examines this proposition by studying in depth the case of ‘Fair & Lovely,’ a skin whitening cream marketed by Unilever in many countries in Asia and Africa, and, in particular, India. Fair & Lovely is indeed doing well; it is a profitable and fast‐growing brand. It is, however, not doing good, and I demonstrate its negative implications for public welfare. I conclude with thoughts on how to reconcile this divergence between private profits and public welfare. Copyright © 2007 John Wiley & Sons, Ltd.
Competing in the looking‐glass market: imitation, resources, and crowding
Authors: Dobrev Stanislav D.
Published: August 2007

I examine two dominant processes of organizational interdependence—imitation and resource competition—and develop a theory that integrates predictions about firms' propensity to change market locations based on both. The cornerstone of the model is the argument that both processes operate concurrently and are driven by the departure of peer firms from a shared resource space. I also argue that the imitation effect, which reflects shared perceptions and interpretations among ecologically proximate peers, hinges on the competitive intensity faced by each individual organization in its market location. Analyses of U.S. automobile manufacturers' moves between the industry's three main market segments confirm the predictions of the theory and point to the merits of using an ecological approach to the evolution of market segmentation and the formation of industry structure. Copyright © 2007 John Wiley & Sons, Ltd.
Measurement practices in financial software industry
Authors: Savioja Erkki , Tukiainen Markku
Published: August 2007

Measurement is practiced in a large number of software organisations. Measurement may have many purposes, e.g. it can have a business goal orientation and software improvement orientation. It is an essential part of the processes in a software company. One of its benefits is that it can be used for customer satisfaction and trust building to show the value creation that quality work has for the customer. Measurement alone will not improve the software process, but it is a necessary step to collect information on the state of affairs and to evaluate the effort in software improvement activities. In this article, we will describe a measurement program in effective use in a medium‐size Finnish software company, which combines in its measurement procedures business goal orientation and a dimension of software process improvement from the perspective of engineering processes. Copyright © 2007 John Wiley & Sons, Ltd.
Invariant torsion properties of multistorey asymmetric buildings
Authors: Doudoumis I. N. , Athanatopoulou A. M.
Published: August 2007

In this paper significant invariant torsion properties of multistorey asymmetric diaphragm systems are presented and investigated, which do not depend on certain special characteristics of the structural system, but only on the vertical distribution of the lateral loading. The analytical study includes generalization of the application of existing formulas for finding the exact location of the optimum torsion axis, verification for its uniqueness, evaluation of the principal torsion directions for any position of the loading axis, and especially for the position of the optimum torsion axis. It also provides quantitative criteria to ascertain whether the diaphragm rotations in general are sufficiently small, when static analysis procedures of calculating the seismic response are going to be applied. Several numerical examples demonstrate the applicability of the proposed methodology, which helps to a better understanding of the torsional behaviour of multistorey buildings. Copyright © 2007 John Wiley & Sons, Ltd.
A procedure for creep and shrinkage analysis of frames with low beam stiffness
Authors: Sharma R. K. , Nagpal A. K.
Published: August 2007

Adjacent vertical members in tall buildings undergo differential time‐dependent deformations due to creep and shrinkage. These deformations result in differential deflections at floor levels and redistribution of forces. An available practical procedure in the literature to estimate these deformations, taking into account the sequential nature of the loading, utilizes the rate of creep method (RCM) to evaluate the stress transfer between concrete and steel. This procedure is designated as Procedure(RCM) and is prone to errors since the creep recovery of concrete is neglected in RCM. A more accurate procedure designated as Procedure(AEMM) using the age‐adjusted effective modulus method (AEMM) as a stress transfer method, and taking into account the sequential nature of the loading, is proposed. The proposed procedure is more accurate than Procedure(RCM) since creep recovery of concrete is considered in AEMM. Numerical studies are carried out in this paper to compare the results from these two procedures. Copyright © 2007 John Wiley & Sons, Ltd.
A new set of design aids for groups of four cylindrical silos due to interstice and internal loadings
Authors: Yuksel S. Bahadir , Arikan Serkan
Published: August 2007

The computation of design forces for reinforced concrete groups of four cylindrical silos requires significant computational effort due to continuity in the walls between adjacent silos. This paper presents a simple but accurate procedure for the computation of design forces acting on groups of four cylindrical silos due to stored materials. In this conjunction, finite element analyses were performed by using eight‐node solid elements for various groups of four cylindrical silos under interstice and internal loadings. The design forces at the prescribed sections of interstice and external walls were computed. The silo wall thicknesses, intersection wall thicknesses and intersection wall lengths of these grouped silos were varied with an extensive parametric study to demonstrate their influences on resultant design forces. Design formulas were proposed and dimensionless design coefficients were derived from the comprehensive series of finite element analyses considering the effect of continuity in the walls. The results were expressed in simplified form, so that the prediction of bending moments, axial forces and shear forces became straightforward for design purposes. In addition, the rigidity of the interstice walls was varied by changing the modulus of elasticity and the redistribution of design forces was investigated. Copyright © 2007 John Wiley & Sons, Ltd.
Middle cerebral artery blood flow velocities and pulsatility index and the cerebroplacental pulsatility ratio: longitudinal reference ranges and terms for serial measurements
Authors: Ebbing C. , Rasmussen S. , Kiserud T.
Published: August 2007

Objectives

To establish reference ranges suitable for serial assessments of the fetal middle cerebral (MCA) and umbilical (UA) artery blood flow velocities, pulsatility index (PI) and cerebroplacental pulsatility ratio and to provide terms for calculating conditional reference intervals suitable for individual serial measurements.

Methods

This was a longitudinal study of 161 singleton pregnancies. Using Doppler ultrasound, MCA and UA blood velocities and PI were determined three to five times at 3–5‐week intervals over a gestational age range of 19–41 weeks. Polynomial regression lines for the 95th, 50th and 5th percentiles were calculated for the peak systolic velocity (PSV), time‐averaged maximum velocity (TAMXV), PI and cerebroplacental ratio. Terms for calculating conditional reference intervals were established.

Results

Based on 566 observations our new longitudinal reference ranges for fetal middle cerebral PSV, TAMXV and PI provided terms for calculating conditional reference intervals (i.e. predicting expected 95% confidence limits based on a previous measurement), and correspondingly for the cerebroplacental ratio (n = 550). The reference ranges were at some variance with those of previous cross‐sectional studies. The narrow 95% confidence limits for the 5th and 95th percentiles ensured reliable ranges.

Conclusions

We have established longitudinal reference ranges appropriate for the serial assessment of MCA blood velocities and PI and cerebroplacental ratio. Particularly the terms for calculating conditional ranges based on a previous observation make this system more appropriate for longitudinal monitoring than are cross‐sectional data. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Likelihood ratios for fetal trisomy 21 based on nasal bone length in the second trimester: how best to define hypoplasia?
Authors: Cusick W. , Shevell T. , Duchan L. S. , Lupinacci C. A. , Terranova J. , Crombleholme W. R.
Published: August 2007

Objective

To determine the best measure of fetal nasal bone hypoplasia for trisomy 21 risk assessment in the second trimester.

Methods

This was a prospective, observational study performed at a single institution between February 2003 and December 2005. Fetuses with nasal bone length recorded sonographically between 16 and 20.9 weeks and known karyotype were included. Definitions of nasal bone hypoplasia assessed included: non‐visualized nasal bone, nasal bone < 10th percentile, nasal bone < 2.5th percentile, biparietal diameter/nasal bone ratio ≥ 10 and ≥ 11 and nasal bone multiples of the median (MoM) ≤ 0.5, ≤ 0.6, and ≤ 0.7.

Results

A total of 371 chromosomally normal and 11 trisomy 21 fetuses were included. Nasal bone hypoplasia based on MoM was superior to the other measures of hypoplasia for trisomy 21 risk assessment as reflected by a higher positive likelihood ratio. The risk for fetal trisomy 21 was higher with greater degrees of nasal bone hypoplasia.

Conclusion

Hypoplasia, as defined by MoM, is the superior approach when incorporating nasal bone evaluation into fetal trisomy 21 risk assessment in the second trimester. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Gastrointestinal stromal tumors mimicking gynecological masses on ultrasound: a report of two cases
Authors: Pinto V. , Ingravallo G. , Cicinelli E. , Pintucci A. , Sambati G. S. , Marinaccio M. , D'Addario V.
Published: August 2007

Gastrointestinal stromal tumors (GISTs) are among the most common mesenchymal tumors of the gastrointestinal tract. Diagnosis of GIST on ultrasound examination can be difficult because of their similarity in appearance to gynecological neoplasms. We present two cases of GIST originating from the small bowel and the stomach, which were preoperatively misdiagnosed as a uterine leiomyoma and an ovarian tumor, respectively. The ultrasonographic differential diagnosis of these pelvic masses is discussed. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Reversed end‐diastolic flow in the umbilical artery at 10–14 weeks of gestation is associated with absent pulmonary valve syndrome
Authors: Berg C. , Thomsen Y. , Geipel A. , Germer U. , Gembruch U.
Published: August 2007

Objective

To determine the incidence of reversed end‐diastolic flow (REDF) in the umbilical artery in high‐risk first‐trimester pregnancies and evaluate associated conditions.

Methods

This was a prospective evaluation of the umbilical artery Doppler waveforms of 614 consecutive high‐risk pregnancies between 10 and 14 weeks of gestation, to determine those with REDF. The associated anomalies and characteristics of these fetuses were then investigated.

Results

In 278/614 (45.3%) fetuses, there was positive end‐diastolic flow in the umbilical artery; in 331/614 (53.9%) end‐diastolic flow was absent and in 5/614 (0.8%) there was REDF. Three of the five fetuses with REDF had tetralogy of Fallot (TOF) with absent pulmonary valve syndrome (APVS) and a patent ductus arteriosus, and all three showed signs of cardiac failure, with reversed blood flow in the ductus venosus during atrial systole and generalized skin edema. Another fetus had a large ventricular septal defect and the remaining fetus had agenesis of the ductus venosus. Three fetuses had trisomy 18 and one had trisomy 13.

Conclusions

REDF in the umbilical artery is very rare in early pregnancy and mostly occurs in association with major fetal vascular anomalies and cardiac defects, particularly TOF with APVS and patent arterial duct. We propose that the patency of the arterial duct in TOF with APVS leads to heart failure with subsequent demise early in pregnancy. Therefore, the frequent absence of the arterial duct observed in APVS in later pregnancy is more likely to be a result of early selection than a prerequisite for the development of this lesion as has been proposed previously. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
A novel distributed MCDS approximation algorithm for wireless sensor networks
Authors: Xie Rong , Qi Deyu , Li Yongjun , Wang James Z.
Published: August 2007

Since finding the minimum connected dominating set (MCDS) in an arbitrary graph is a NP‐hard problem, many algorithms have been proposed to construct an approximation of the MCDS for efficient routing in wireless sensor networks (WSNs). To address the weaknesses of these existing algorithms, we propose a novel distributed MCDS approximation algorithm, CDS‐HG, to construct the connected dominating set (CDS) for WSNs. This algorithm models a WSN as a hierarchical graph and uses a competition‐based strategy to select nodes at a certain hierarchical level to route messages for nodes in the next level of the hierarchical graph. Formal analysis and simulation studies show that our CDS‐HG algorithm generates smaller CDS sizes while requiring less communication overhead compared with the existing distributed MCDS approximation algorithms. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis and Crystal Structure of {[Hg(RNNNR′)2]2}∞ [R = 4‐C2H5OC(O)C6H4, R′ = 2‐FC6H4] – an Asymmetric 1,3‐Diaryltriazenide Complex of Mercury(II) with 1D Supramolecular Arrangement through Hg‐η2,η2′‐Arene π–Interactions
Authors: Hörner Manfredo , Broch Fernanda , do Canto Visentin Lorenzo
Published: August 2007

The reaction of 1‐(4‐ethoxycarbonylphenyl)‐3‐(2‐fluorophenyl)triazene with mercury(II) acetate in the presence of potassium methanolate in methanol yields [Hg(RNNNR′)2] [R = 4‐C2H5OC(O)C6H4, R′ = 2‐FC6H4] as light‐yellow crystals. [Hg(RNNNR′)2] complex molecules are associated to [Hg(RNNNR′)2]2 dimeric units through centrosymmetric metal‐η2‐arene π‐interactions. The dimeric units – related to each other by translation – self‐assemble to one‐dimensional chains along to the crystallographic direction [110] through additional centrosymmetric metal‐η2‐arene π‐interactions giving rise to a supramolecular 1D arrangement. The [Hg(RNNNR′)2]2 dimeric units are also characterized by non‐classical intermolecular C‐H···O, and intramolecular C‐H···F hydrogen bonds involving the 4‐EtOC(O) and 2‐F substituents, respectively.
Chiral Metal Complexes with the Biologically Active (+)‐Pilocarpine Ligand: [MCl2(κN‐(+)‐pilocarpine)2] (M = Co, Cu)
Authors: Wisser Barbara , Janiak Christoph
Published: August 2007

The enantiopure ligand (+)‐pilocarpine [(3S,4R)‐3‐ethyl‐dihydro‐4‐((1‐methyl‐1H‐imidazol‐5‐yl)methyl)furan‐2(3H)‐one] from the chiral pool coordinates with the imidazole nitrogen atom to transition metal atoms. Complexes [MCl2(κN‐(+)‐pilocarpine)2] (M =Co, Cu) crystallize as pseudo‐tetrahedral (M = Co) or distorted in‐between tetrahedral and square‐planar (M = Cu) molecules. Supramolecular C‐H···Cl contacts are seen in the crystal packing. In aqueous solution the tetrahedral cobalt complex expands its coordination sphere to pseudo‐octahedral through the addition of two water molecules as indicated by the reversible color change between blue (solid, non‐aqueous solution) and pink.
Exploring the Interaction of Anthracene‐Containing Macrocyclic Chemosensors with Silver(I) and Cadmium(II) Ions – Photophysical and Structural Studies
Authors: Tamayo Abel , Oliveira Elisabete , Covelo Berta , Casabó Jaume , Escriche Lluís , Lodeiro Carlos
Published: August 2007

The four anthracene‐containing macrocycles 7‐(9anthracenylmethyl)‐3,11‐dithia‐7,17‐diazabicyclo[11.3.1]heptadeca‐1(17),13,15‐triene (L1), 7‐(10‐methyl‐9‐anthracenylmethyl)‐3,11‐dithia‐7,17‐diazabicyclo[11.3.1]heptadeca‐1(17),13,15‐triene (L2), 7,7′‐[9,10‐anthracenediylbis(methylene)]bis‐3,11‐dithia‐7,17‐diazabicyclo[11.3.1]heptadeca‐1(17),13,15‐triene (L3), and 11,‐(anthracen‐9‐ylmethyl)‐1,4,7‐trithia‐11‐azacyclotetradecane (L4), have been explored as fluorescent chemosensors for the sensing of the d10 metal ions AgI and CdII. The compositions of the formed species have been determined from absorption and fluorescence titrations. The binding properties of L1 were also studied in the solid state. The synthesis and crystallographic characterization of complex [Cd(NO3)2(L1)] are discussed.
Reactions of Transition Metal Azido Complexes and their Reaction Products
Authors: Strähle Joachim
Published: August 2007

Transition metal azido complexes can undergo various reactions of their azido group to yield interesting products. The cleavage of the Naα‐Nβ bond and elimination of molecular nitrogen can generate nitrido complexes like MoNCl3 or WNCl3, chloroiminato complexes like Cl3VNCl, or phosphoraneiminato complexes like [Cl4NbNPPh3]2 with metal nitrogen multiple bonds. The reductive elimination of the complete azido group on the other hand may produce metal(0) fragments which in case of gold(I) azido complexes can combine to form clusters.
[(Me3Si)2N]3Lu: Molecular Structure and Use as Lu and Si Source for Atomic Layer Deposition of Lu Silicate Films
Authors: Scarel G. , Wiemer C. , Fanciulli M. , Fedushkin I. L. , Fukin G. K. , Domrachev G. A. , Lebedinskii Y. , Zenkevich A. , Pavia G.
Published: August 2007

The molecular structure of tris[bis(trimethylsilyl)amido]lutetium, [(Me3Si)2N]3Lu, is investigated. An agostic interaction is found between Lu and the Si atom of the silyl group. The performance of [(Me3Si)2N]3Lu as precursor to deposit Lu silicate layers by atomic layer deposition using either H2O or O3 as oxygen source is studied. Si incorporation in the films is revealed: [(Me3Si)2N]3Lu thermal decomposition and the mentioned agostic interaction contribute both to the phenomenon. [(Me3Si)2N]3Lu thermal decomposition also affects the growth rate of films deposited using H2O. The growth rate of films deposited using O3, especially at growth temperatures < 300 °C, is extremely high, probably because of the hydrogen atoms existing in [(Me3Si)2N]3Lu.
Spectroscopic and Magnetic Properties of Co1.7Mn0.3(OH)PO4
Authors: de Pedro I. , Rojo J. M. , Lezama L. , Rojo T.
Published: August 2007

Co1.7Mn0.3(OH)PO4 has been prepared under mild hydrothermal conditions and characterized from powder X‐ray diffraction. IR data are characteristic of three distinct features corresponding principally to the vibrations of the hydroxide and [PO4]3− anions. UV‐Visible studies show the existence of bands ascribed to the chromophores of Co ions in two coordination polyhedra, octahedral and trigonal bipyramidal. The magnetic behaviour indicates the existence of antiferromagnetic interactions as predominant. Magnetization measurements show the presence of two maxima at 65 K and 9 K, respectively. The first peak was attributed to a three‐dimensional antiferromagnetic ordering and the second one reveals the possible existence of a spin‐glass like state. The substitution of Co2+ (S = 3/2) by Mn2+ (S = 5/2) ions at about 15 % keeps the two magnetic transitions observed in the non‐substituted phase. ZFC‐FC curves show magnetic irreversibility at temperatures just below TN due to the spin decompensations in Co1.7Mn0.3(OH)PO4. The remanent magnetization indicates higher ferromagnetic interactions at lower temperatures than that observed in the ordered Co2(OH)PO4 phase. These results could be attributed to the existence of a spin‐glass state similar to that exhibited by the Co2(OH)PO4 and substituted Co2−xMx(OH)PO4 (M = Ni, Cu; x = 0.1−0.3) compounds. A comparative magnetic study with the analogous Ni2+ (S = 1) and Cu2+ (S = 1/2) phases is carried out.
Solid State Conformational Features of Homodinuclear Nickel Complexes Double Bridged by Phosphate Esters and Related Ligands
Authors: Pérez José , García Luis , Carrascosa Ramón , Pérez Eduardo , Serrano Jose Luis , Sánchez Gregorio , García Gabriel , Santana Dolores , López Luisa , García Joaquí
Published: August 2007

Solid state coordination geometry (distances, angles) in the titled complexes has been statistically characterized. Data have been extracted from the Cambridge Structural Database (CSD) and from three new crystal structures reported in this paper. The conformation adopted by the 8‐membered ring defined by nickel atoms and bridging ligands has been characterized by a probabilistic method in complexes [{NiL(μ‐O2P(OR)2)}2] (L = hydrotris(3,5‐dimethylpyrazolyl)borate, R = Me, Ph). The observed and ideal conformations have been studied by Molecular Mechanics. The strain energy calculated for the observed conformations is clearly lower, justifying their appearance in the solid state.
Synthesis, Structural Characterization and Electrochemical Studies of a Nicotinamide‐bridged Dinuclear Copper Complex derived from a Tridentate Hydrazone Schiff Base Ligand
Authors: Monfared Hassan Hosseini , Kalantari Zahra , Kamyabi Mohammad‐Ali , Janiak Christoph
Published: August 2007

The in‐situ formed hydrazone Schiff base ligand (E)‐N′‐(2‐hydroxy‐3‐methoxybenzylidene)benzohydrazide (H2L1) and nicotinamide (L2) give the copper(II) complex [CuL1L2] on reaction with copper(II) acetate. In the solid state two copper atoms are linked by nicotinamide through coordination with its pyridyl nitrogen atom and its amide‐C=O group to the dicopper(II) complex [CuL1(μ‐L2)CuL1L2]. The coordination polyhedra are a CuO2N2 square and a CuO3N2 square pyramide. Cyclic voltammetric experiments of the solution species [CuL1L2] in DMF reveal reduction of the L1 ligand at three potentials with a reduction at −0.5 V resulting in decomposition of the complex.
Cation Ordering and Electrical Properties of the Ruddlesden‐Popper Gd2−2xSr1+2xCo2O7 Compounds (x = 0 and 0.10)
Authors: Sánchez‐Andújar M. , Señarís‐Rodríguez M. A.
Published: August 2007

We report the structure and microstructure of the Ruddlesden‐Popper (RP) series n=2 Gd2−2xSr1+2xCo2O7 (x = 0 and 0.10). X‐ray powder diffraction, electron diffraction and HRTEM indicate that these compounds have a tetragonal structure (space group: P42/mnm) with cell parameters a ≈ 5.3749Å c ≈ 19.3591Å, in which the [CoO6] octahedra are distorted and tilted. Also, very interestingly, according to the obtained results these compounds presents A‐site cation ordering where the divalent and bigger Sr2+ cation selectively prefers the 12‐coordinated P site while the smaller and trivalent Gd3+ cation prefers the 9‐coordinated R site. From the electrical point of view these materials are semiconducting and their resistivitiy decreases upon doping. In addition, the highest doped sample presents a small magnetoresistive effect MRmax = −3.2 % under Hmax = 50 kOe at T = 55 K.