bluuebunny/crossref_metadata_2025 huggingface dataset:
On‐farm management practices to minimise off‐site movement of pesticides from furrow irrigation
Authors: Oliver Danielle P , Kookana Rai S
Published: August 2006

Off‐site movement of pesticides from furrow‐irrigated agriculture has been a concern in the Ord River Irrigation Area, Western Australia. This paper reports on the effectiveness of incorporation of pesticides by cultivator or power harrows before irrigating, and spraying pesticides only onto beds to minimise off‐site transport. Incorporation of pesticides by power harrows prior to irrigation was found to be more effective in decreasing the off‐site transport of a more strongly sorbed pesticide, endosulfan. The average load of total endosulfan (α + β + sulfate) decreased by 74% (P < 0.01) from 11.41 g ha−1 from the conventionally treated bays to 2.96 g ha−1 from the incorporated irrigation bays. The total average load of atrazine leaving the irrigation bays was decreased by 81% (P < 0.05) from 87.82 g ha−1 under the conventional practice of spraying the whole field to 16.95 g ha−1 by spraying the beds only. A reduction of 52% in total average load of metolachlor was observed following incorporation with power harrows, but this was not significant. Incorporation by cultivator or by power harrows decreased the total load of atrazine or metolachlor leaving the irrigation bays over the whole irrigation period, but these treatments were not shown to be statistically significant, which may have been due to the limited number of field replicates. Incorporation of strongly sorbed pesticides (e.g. endosulfan) prior to irrigation significantly decreased the off‐site transport of these pesticides in a furrow irrigation system and may be a useful practice to minimise off‐site transport of other similar pesticides. Minimising off‐site transport of weakly sorbed pesticides (e.g. atrazine and metolachlor) from a furrow irrigation system is more difficult. The nature of furrow irrigation makes it highly conducive to pesticide transport, particularly of weakly sorbed pesticides, and further work is needed to develop strategies to minimise the movement of this group of pesticides to water bodies. Copyright © 2006 Society of Chemical Industry
Use of crop residues for the control of Meloidogyne incognita under laboratory conditions
Authors: PiedraBuena Ana , García‐Álvarez Avelino , Díez‐Rojo Miguel Á , Bello Antonio
Published: August 2006

This laboratory study evaluates the biofumigant effect of different organic materials with the aim of developing non‐chemical alternatives for the management of Meloidogyne incognita (Kofoid & White) Chitwood populations. Sources of organic material from the production system were selected with the aim of reducing agricultural residue accumulation problems as well as decreasing the costs due to the use of chemical fertilizers and pesticides. The selected materials were residues from pepper, strawberry, tomato and cucumber crops, orange juice industry residues, commercial manure and sheep manure, applied at different dosages. Two biofumigation assays were performed under laboratory conditions, using alkaline soils from the Torreblanca area (Murcia, Spain) and acidic soils from the Villa del Prado area (Madrid, Spain). The assays evaluated the effect of the treatments on M. incognita juveniles and other soil organisms, the nematode galling index on tomato roots (susceptible cv. Marmande) grown in the biofumigated soil and soil fertility parameters. The results showed that all biofumigant materials significantly decreased M. incognita populations and galling indices in tomato cv. Marmande. A greater effect was observed on galling indices when applying crop residues together with manure than with the residues alone. Biofumigation had a general beneficial effect on soil fertility, generally increasing nitrogen, organic carbon, pH and potassium levels, and also calcium levels when crop residues of pepper and strawberry were applied. There were no important variations in the number of saprophagous nematodes, dorylaimids and enchytraeids. Copyright © 2006 Society of Chemical Industry
Relationship between esterase activity and acrinathrin and methiocarb resistance in field populations of western flower thrips, Frankliniella occidentalis
Authors: Maymó Ana C , Cervera Amelia , Dolores Garcerá M , Bielza Pablo , Martínez‐Pardo Rafael
Published: August 2006

The western flower thrips, Frankliniella occidentalis (Pergande), is a serious pest in the south‐east of Spain owing to its direct feeding on crops, transmission of the tomato spotted wilt virus and its very high level of resistance to insecticides. Mechanisms of resistance were examined using field populations of F. occidentalis with different susceptibilities to acrinathrin, methiocarb (selective insecticides), endosulfan, metamidophos and deltamethrin (broad‐spectrum insecticides). Esterase activity towards α‐naphthyl acetate and p‐nitrophenyl acetate in resistant strains was significantly higher than in the reference strain (MLFOM) for both model substrates. This higher activity was significantly correlated with acrinathrin and methiocarb resistance. Copyright © 2006 Society of Chemical Industry
Advances in serviceability and strength of normal‐ and high‐strength concrete structures
Authors: Loo Yew‐Chaye , Huq Chowdhury Sanaul
Published: August 2006

Serviceability and strength of concrete structures have been a topic of intense research for many years. Reported herein is the work conducted in this area, especially in the past decade, which ranges from the development of the layered finite element method and the associated theoretical studies to elaborate laboratory tests of high‐strength concrete elements. In particular, serviceability studies reviewed include natural frequency, cracking and crack patterns, deflection and damping characteristics; strength investigations reviewed cover beams, slabs and walls, as well as the punching shear strength of flat plates. A long‐term on‐site study of column shortening in an 80‐storey residential building recently completed at Gold Coast in Southeast Queensland, Australia is also reported. In addition, a separate section discusses the serviceability studies specific for high‐strength concrete structures. Summarized herein is the review of research findings published during the period spanning mainly from 1995 to 2005. Relevant formulas and analytical procedures which may assist practising engineers in the design of concrete structures are reported for completion. Copyright © 2006 John Wiley & Sons, Ltd.
Electric transport perpendicular to the planes
Authors: Herper H. C.
Published: August 2006

Since the discovery of the giant magnetoresistance (GMR) in magnetic multilayers, several theoretical descriptions have been used to determine the resistivity of such layered structures. The resistance for the current in direction of the planes of layers can easily be measured, and has been intensively studied theoretically. However, the investigation of the GMR for the current perpendicular to the planes (CPP) is slightly more difficult. Here, a microscopic formalism for the study of the CPP GMR is reported by making use of the Kubo–Greenwood equation. Within this method perturbations of the interfaces like interdiffusion, alloy formation, or impurities can easily be included, which is of importance, because the discussion of the GMR is always related to the structure of the interfaces. The presentation of the Kubo–Greenwood formalism for CPP transport is complemented by a brief discussion of some exemplary results. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cover picture: Extrinsic defect structure of RE3Al5O12 garnets
Authors: Stanek C. R. , McClellan K. J. , Levy M. R. , Grimes R. W.
Published: August 2006

The cover picture of Rapid Research Letters refers to the article [1] by Chris Stanek et al. The image visually describes the results of calculations pertaining to the defect structure in rare earth aluminum garnet corresponding to Me2+ and Me4+ dopants. In particular, this result aids the development of garnet scintillators.
Scientific Highlights from the Ψk Network: Towards Atomistic Materials Design
Authors: Dederichs P. H. , Szotek Z. (Dzidka) , Ordejon P.
Published: August 2006

The Ψk network aims at encompassing the whole community of European groups working in the area of ab‐initio materials modelling, including very many small groups and isolated researchers. Historically, the activities started in the 1980s in Trieste with the workshop series entitled “Total Energies and Forces”. Since then, it has operated on the European level in various forms, with funding from various EC/EU and ESF sources, beginning more than 10 years ago with the EC's Human Capital and Mobility Programme. In that time, Ψk has done much to make Europe the leading area in the world for research in atomic‐scale ab‐initio computer simulation of all types of materials, their structures, properties, and processes. To a large extent, this has been done by nurturing scientific excellence and collaboration in what might be called “the Ψk family”. The Ψk Network is presently organized around 15 topical working groups. Over the years, the Ψk network organized three large scale conferences in Schwäbisch Gmünd, Germany (1996, 2000, 2005), attended by hundreds of scientists from all over the world. The next Ψk Conference is to be organized in Berlin in 2010. These Ψk Conferences are unique events fully dedicated to the ab‐initio research. In addition, the network organizes a variety of meetings and topical workshops every year.

The core activities of the Ψk network involve editing every two months a Ψk newsletter with typically more than 100 pages, which contains a “Scientific Highlight”, announcements of conferences, workshops and vacant positions, news of various ESF and EU funded networks, including reports on workshops, and abstracts of submitted papers. The Ψk has its own web pages (http://psi‐k.dl.ac.uk) which inform about the Network, its structure, and how to get involved in Ψk activities. These web pages are also the repository of the Ψk newsletters and Scientific Highlights and details about the Ψk Workshops of the most recent years. The Ψk mailing list contains about 1700 e‐mail addresses from across the world, and all the important information about a variety of activities of the network is distributed across this list on a daily basis.

The “Scientific Highlights” of the Ψk newsletters reflect the scientific activities of the network and aim at presenting reviews and current developments in the field. This special issue of physica status solidi (b) gives a collection of some of the most recent Highlight contributions to the Ψk newsletter. All manuscripts originally posted on the Ψk server were peer‐reviewed by two referees and accepted according to the standards of pss. They are published here partly in revised or updated version. We hope that the readership of the journal will benefit from the quality of the research they report on and the high level of the presentations.
Power and sample size considerations in clinical trials with competing risk endpoints
Authors: Maki Ellen
Published: August 2006

In clinical trials with a time‐to‐event endpoint, subjects are often at risk for events other than the one of interest. When the occurrence of one type of event precludes observation of any later events or alters the probably of subsequent events, the situation is one of competing risks. During the planning stage of a clinical trial with competing risks, it is important to take all possible events into account. This paper gives expressions for the power and sample size for competing risks based on a flexible parametric Weibull model. Nonuniform accrual to the study is considered and an allocation ratio other than one may be used. Results are also provided for the case where two or more of the competing risks are of primary interest. Copyright © 2006 John Wiley & Sons, Ltd.
A case study comparing a randomized withdrawal trial and a double‐blind long‐term trial for assessing the long‐term efficacy of an antidepressant
Authors: Mallinckrodt Craig , Chuang‐Stein Christy , McSorley Paul , Schwartz Jeffrey , Archibald Donald G. , Perahia David G. , Detke Michael J. , Alphs Larry
Published: August 2006

Assessing long‐term efficacy in psychiatric drugs involves a number of complex questions, and the priaority of these questions is different for different disorders and for different stakeholders. Therefore, it is essential that we not adopt a one‐method‐fits‐all approach, but rather adapt the specific details of the designs and analysis of data from long‐term trials to individual disease states. Randomized withdrawal (RW) designs, even though addressing a specific question of particular interest, face some difficult methodological and ethical challenges. A less common alternative design, termed the double‐blind long‐term efficacy (DBLE) design, is logistically similar to traditional responder extension designs. However, use of an analytic approach that includes all randomized patients rather than only the selected subset that continued beyond acute treatment avoids the major criticism of the extender design. The present paper illustrates the attributes of the RW and DBLE designs by analyzing data from trials adopting these designs. The RW and DBLE designs address different questions, and are thus not directly comparable. Potential benefits of the DBLE design include: (1) the parsimonious use of patients and the resultant reduced exposure to placebo as each patient can contribute to multiple developmental objectives; (2) the results are generalizable to actual clinical practice as the design matches treatment guidelines; and, (3) results of safety assessments are meaningful as they involve all randomized patients. Our case study suggests that the DBLE design can provide definitive answers to important questions and may be a useful design for assessing long‐term treatment effects. Copyright © 2006 John Wiley & Sons, Ltd.
Effect of rosmarinus officinalis in modulating 7,12‐dimethylbenz(a)anthracene induced skin tumorigenesis in mice
Authors: Sancheti Garima , Goyal P. K.
Published: August 2006

The chemopreventive potential of rosemary (Rosmarinus officinalis) on 7,12‐dimethlybenz(a)anthracene (DMBA) initiated and croton oil promoted mouse skin tumorigenesis was assessed. The modulatory effects of R. officinalis was monitored on the basis of the average latency period, tumor incidence, tumor burden, tumor yield, tumor weight and diameter as well as lipid peroxidation and glutathione level. The results indicate that R. officinalis leaves extract could prolong the latency period of tumor occurrence, decrease the tumor incidence, tumor burden and tumor yield. The average weight and diameter of tumors recorded were comparatively lower in the rosemary extract treated mouse groups. The level of lipid peroxidation was significantly reduced in blood serum and liver. Furthermore, depleted levels of glutathione were restored in RE‐administered animal groups. Thus, at a dose rate of 500 mg/kg body wt/mouse, the oral administration of rosemary extract was found to be significantly protective against two‐stage skin tumorigenesis. Copyright © 2006 John Wiley & Sons, Ltd.
A review of the bioactivity of south African herbal teas: rooibos (Aspalathus linearis) and honeybush (Cyclopia intermedia)
Authors: McKay Diane L. , Blumberg Jeffrey B.
Published: August 2006

Rooibos (Aspalathus linearis) and honeybush (Cyclopia intermedia) are popular tisanes in their native South Africa and have a growing worldwide market. Both herbal teas are used traditionally for medicinal purposes and are rich in polyphenols with rooibos a rare source of the dietary dihydrochalcones, aspalathin and nothofagin. The principal polyphenols in honeybush include the xanthone mangiferin and the flavonones hesperitin and isokuranetin. Despite their divergent phytochemical and nutrient compositions, rooibos and honeybush share potent antioxidant and antimutagenic activities in vitro. Animal model studies indicate both herbal teas possess potent antioxidant, immune‐modulating and chemopreventive actions. However, human studies of rooibos are limited and of honeybush are absent. No adverse effects of rooibos or honeybush consumption as tisanes have been reported. Copyright © 2006 John Wiley & Sons, Ltd.
QSAR Prediction of the Penetration of Drugs Across a Polydimethylsiloxane Membrane
Authors: Ma Weiping , Luan Feng , Zhao Chunyan , Zhang Xiaoyun , Liu Mancang , Hu Zhide , Fan Botao
Published: August 2006

A quantitative structure–activity relationship was developed by the Heuristic Method (HM) to study the penetration of 245 drugs across a polydimethylsiloxane membrane. The descriptors in this study were calculated by the software CODESSA. HM was used both for preselecting molecular descriptors and for developing the linear model. Logarithms of the maximum steady‐state flux (J) values are correlated with four descriptors, with a squared correlation coefficient (R2) of 0.844 and root‐mean‐square error of 0.438, respectively. These four theoretical molecular descriptors are count of H‐acceptor sites, gravitation index, H‐donors charged surface area, and weighted positive‐charged partial surface area. The rationality of the descriptors was evaluated by similarity analysis, while the stability and validity of the model was evaluated by validation. This paper provides a simple and straightforward way to predict the log J values of the drugs from their structures alone and gives some insight into structural features related to the penetration of drugs.
Theory of chemical bonds in metalloenzymes III: Full geometry optimization and vibration analysis of ferredoxin‐type [2Fe–2S] cluster
Authors: Shoji Mitsuo , Koizumi Kenichi , Taniguchi Takeshi , Kitagawa Yasutaka , Yamanaka Shusuke , Okumura Mitsutaka , Yamaguchi Kizashi
Published: August 2006

The nature of chemical bonds in a ferredoxin‐type [2Fe–2S] cluster has been investigated on the basis of natural orbitals and several bond indices developed in Parts I and II of this study. The broken‐symmetry hybrid density functional theory (BS‐HDFT) with spin projection approach has been applied to elucidate the natural orbitals and occupation numbers for a model compound [Fe2S2(SCH3)4] (1), which is used to calculate the indices. The molecular structure, vibration frequencies, electronic structures, and magnetic properties in both oxidized and reduced forms of 1 have been calculated and compared with the experimental values. The optimized molecular structures after approximate spin projection have been in good agreement with experimental data. The structure changes upon one‐electron reduction have been slight (<0.1 Å) and only limited around one side of the Fe atom. Raman and infrared (IR) spectra have been calculated, and their vibration modes have been assigned using the bridging34S isotope substitution. Their magnetic properties have been examined in terms of spin Hamiltonians that contain exchange interactions and double exchange interactions. The BS‐HDFT methods have provided the magnetic parameters; i.e., effective exchange integral (J) values and valence delocalization (B) values, which agree with the experimental results. It is found that large charge transfer (CT) from the bridging sulfur to the iron atoms has led to the strong antiferromagnetic interactions between iron atoms. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Theoretical study of the · H reaction with cytosine
Authors: Zhang Hongyu , Liang Qimin , Xia Yueyuan , Zhao Mingwen , Ji Yanju , Song Chen , Liu Xiangdong , Zhang Bingyun
Published: August 2006

We studied three possible reactions of H atom attacking the cytosine, using density functional theory (DFT) calculations. The results indicate that the H atom addition to the N3 site of cytosine is energetically more favorable than to the C5 or C6 site. The reaction of addition to the C6 site has an energy barrier of ∼2.77 kcal/mol, which is ∼2 kcal/mol higher than addition to C5. The energy of C5 H‐adduct radical is also lower than that of C6 H‐adduct radical. From the point of view of both energetics and reaction kinetics, the addition of the H atom to the C5 site is preferred to the addition to the C6 site. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Docking stability and electronic structure of azurin–cytochrome c551 complex system
Authors: Sugiyama Ayumu , Takamatsu Yuichiro , Nishikawa Keigo , Nagao Hidemi , Nishikawa Kiyoshi
Published: August 2006

We investigate the docking structure between cytochrome c551 and azurin proteins by quantum mechanical calculation and molecular dynamics (MD). A model for the docking structure of the cytochrome–azurin complex is presented. We calculate the charge distribution around the active site for each protein and force field parameters to simulate the complex system by MD. We estimate some physical properties, such as binding free energy and the dynamical cross‐correlation map. We discuss the stability of the cytochrome c551–azurin complex system. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Development of a liquid chromatography/tandem mass spectrometry assay for the quantification of PM02734, a novel antineoplastic agent, in dog plasma
Authors: Yin Jianming , Aviles Pablo , Lee William , Ly Carl , Guillen Maria Jose , Munt Simon , Cuevas Carmen , Faircloth Glynn
Published: August 2006

A rapid and sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) assay was developed and validated to quantify a novel antineoplastic agent, PM02734, in dog plasma. The method was validated to demonstrate the specificity, limit of quantification (LOQ), accuracy, and precision of measurements. The calibration range for PM02734 was established using PM02734 standards from 0.05 to 100 ng/mL in blank plasma. The dominating ions were doubly charged molecular ions [M+2H]2+ at m/z 740.0 instead of singly charged ones at m/z 1478.4. The selected reaction monitoring (SRM), based on the m/z 740.0 → 212.2 transition, was specific for PM02734, and that based on the m/z 743.8 → 212.2 transition was specific for deuterated PM02734 (the internal standard, IS); no endogenous materials interfered with the analysis of PM02734 and IS from blank plasma. The assay was linear over the concentration range 0.05–100 ng/mL. In terms of sensitivity of assay 0.05 ng/mL is a very low LLOQ, especially considering PM02734 is a peptide. The correlation coefficients for the calibration curves ranged from 0.9990 to 0.9999. The mean intraday and interday accuracies for all calibration standards (n = 9) ranged from 93 to 111% (≤11% bias) in dog plasma, and the mean interday precision for all calibration standards was less than 6.4%. The mean intra‐ and interday assay accuracy for all quality control replicates in dog plasma (n = 9), determined at each QC level throughout the validated runs, ranged from 85–111% (≤15% bias) and from 99–109% (≤9% bias), respectively. The mean intra‐ and interday assay precision was less than 12.1 and 13.3% for all QC levels, respectively. The assay has been used to support preclinical pharmacokinetic (PK) and toxicokinetic studies. The results showed that preclinical samples could be monitored for PM02734 up to 168 h after dosing, which allowed us to identify multiple elimination phases and accurately estimate PK information. Copyright © 2006 John Wiley & Sons, Ltd.
Application of hollow fiber supported liquid membrane extraction to the simultaneous determination of pesticide residues in vegetables by liquid chromatography/mass spectrometry
Authors: Romero‐González Roberto , Pastor‐Montoro Elena , Martínez‐Vidal José Luis , Garrido‐Frenich Antonia
Published: August 2006

A new analytical procedure using a hollow fiber supported liquid membrane (HFSLM) has been developed for the simultaneous determination of pesticide residues in vegetables by liquid chromatography (LC) coupled with electrospray mass spectrometry (MS). The extraction technique requires minimal sample preparation and solvent consumption. Optimum extraction conditions have been evaluated with respect to sample pH, ionic strength, liquid membrane composition, extraction time, stirring rate and acceptor composition. The extraction method has been validated for matrices such as cucumber, tomato and pepper, indicating that cucumber can be selected as representative matrix for routine analysis of these food commodities. Linear ranges of pesticides in vegetable samples were 10 to 200 µg/kg, and the repeatability of the method was less than 20% for the lowest calibration point. The limits of detection ranged from 0.06 to 2.7 µg/kg and the limits of quantification from 0.2 to 9.0 µg/kg, which were low enough to determine the pesticide residues at concentrations below or equal to the maximum residue levels (MRLs) specified by European Union. The method was finally applied to the determination of more than 20 pesticides in market vegetable samples and the concentrations found in these samples were always lower than the MRLs. This new approach can be considered as a powerful alternative to the traditional extraction techniques. Copyright © 2006 John Wiley & Sons, Ltd.
Multiple sclerosis is linked to Epstein‐Barr virus infection
Authors: Haahr Sven , Höllsberg Per
Published: August 2006

The aetiology and pathogenesis of MS are unknown, but environmental agents, genetic susceptibility and stochastic events are likely to be involved. In order to evaluate the possibility that MS is linked to EBV infection, we here evaluate studies on MS‐ and EBV‐epidemiology, prospective and retrospective analysis of EBV‐serology, investigations of EBV DNA sequences in blood and tissues, specificity of antibodies in oligoclonal bands in MS patients and results from antiviral chemotherapy of MS patients. It could be demonstrated that EBV is complying with the epidemiological observations in MS and that all MS patients are seropositive to EBV in contrast to healthy controls. Importantly, despite difficulties in diagnosing child‐MS, the vast majority of these patients are also EBV seropositive. In contrast to control groups, recent EBV infections have never been observed in children or adults with MS. Further prospective studies indicate a 2.8 times higher tendency for development of MS after infectious mononucleosis. In MS patients, unbiased analyses pull out EBV antigens as high‐affinity targets for the antibodies in the oligoclonal bands. Humans are the exclusive natural host for EBV, a finding that may explain why MS is unique to humans. Together these unique observations strongly suggest a linkage between MS and EBV infection. Infection by EBV offers numerable mechanisms to perturb the immune system, including mimicry and superantigen induction, which may potentially participate in the disease mechanisms. In contrast, studies demonstrating higher IgG titres and occurrence of viral DNA in serum/plasma are likely to reflect a consequence of the disease. An explanation for a potential role of respiratory diseases in MS is discussed. It is concluded that the ultimate test to the hypothesis of MS and EBV is the development and application of an EBV vaccine, which is predicted to eradicate the disease. Copyright © 2006 John Wiley & Sons, Ltd.
Virus discovery by sequence‐independent genome amplification
Authors: Ambrose Helen E. , Clewley Jonathan P.
Published: August 2006

Genome sequences from several blood borne and respiratory viruses have recently been recovered directly from clinical specimens by variants of a technique known as sequence‐independent single primer amplification. This and related methods are increasingly being used to search for the causes of diseases of presumed infectious aetiology, but for which no agent has yet been found. Other methods that do not require prior knowledge of the genome sequence of any virus that may be present in the patient specimen include whole genome amplification, random PCR and subtractive hybridisation and differential display. This review considers the development and application of these techniques. Copyright © 2006 John Wiley & Sons, Ltd.
Stability radii of infinite dimensional systems with stochastic uncertainty and their optimization
Authors: Kada M. , E. Rebiai S.
Published: August 2006

In this paper we consider infinite dimensional systems which are subjected to stochastic structured multiperturbations. We first characterize the stability radii of these systems in terms of a Lyapunov equation and the corresponding Lyapunov inequalities. Then we investigate the problem of maximizing the stability radius by linear state feedback. We show that the supremal achievable stability radius can be determined via the resolution of a parametrized Riccati equation. Illustrative examples are included. Copyright © 2006 John Wiley & Sons, Ltd.
Support vector machines‐based generalized predictive control
Authors: Iplikci S.
Published: August 2006

In this study, we propose a novel control methodology that introduces the use of support vector machines (SVMs) in the generalized predictive control (GPC) scheme. The SVM regression algorithms have extensively been used for modelling nonlinear systems due to their assurance of global solution, which is achieved by transforming the regression problem into a convex optimization problem in dual space, and also their higher generalization potential. These key features of the SVM structures lead us to the idea of employing a SVM model of an unknown plant within the GPC context. In particular, the SVM model can be employed to obtain gradient information and also it can predict future trajectory of the plant output, which are needed in the cost function minimization block. Simulations have confirmed that proposed SVM‐based GPC scheme can provide a noticeably high control performance, in other words, an unknown nonlinear plant controlled by SVM‐based GPC can accurately track the reference inputs with different shapes. Moreover, the proposed SVM‐based GPC scheme maintains its control performance under noisy conditions. Copyright © 2006 John Wiley & Sons, Ltd.
Novel down link rain fade mitigation technique for Ka‐band multibeam systems
Authors: Majithiya Parimal , Sisodia A. K. , Muralidhar V. , Garg V. K.
Published: August 2006

Rain fades at Ka‐Band degrades the link quality and performance significantly. Several rain fade mitigation techniques for Ka‐band satellite systems are being investigated to improve the channel capacity. Methods such as power control and adaptive waveform techniques have been proposed for use in the uplink as they are capable of straightforward implementation. A novel down link power control technique for multi‐beam Ka‐band system has been proposed in this paper. It is based on the use of multi‐port amplifier, which is commonly used for dynamic power sharing of the beams depending upon the traffic. Payload architecture for multi‐beam coverage using multi‐port amplifiers has been designed for the proposed technique. The simulation results to compensate for the rain fade attenuation of one beam by sharing the unused power from other beams have been presented Copyright © 2006 John Wiley & Sons, Ltd.
Biostatisticians, biostatistical science and the future
Authors: Zelen Marvin
Published: August 2006

Biostatistical Science is in a ‘golden period’. The definition of Biostatistical Science is the application of statistics, probability, mathematics and computing to advance our understanding of the subject matter in the biomedical sciences. Our field is experiencing unparallel developments due of the advances in communication and computing. We are becoming more global, we have resources which can expand educational opportunities for distant learning; the growth of quantitative methods in the biomedical sciences has made biostatistical science a key component in many research areas. What about the future? Are we receptive to change as many new scientific areas expand? Will the interaction between academia and industry likely to grow—especially in the training of future practitioners of biostatistical science. This paper discusses some of challenges facing our profession if we are to continue to be relevant in the biomedical sciences. Copyright © 2006 John Wiley & Sons, Ltd.
The merits of breaking the matches: a cautionary tale
Authors: Donner Allan , Taljaard Monica , Klar Neil
Published: August 2006

Matched‐pair cluster randomization trials are frequently adopted as the design of choice for evaluating an intervention offered at the community level. However, previous research has demonstrated that a strategy of breaking the matches and performing an unmatched analysis may be more efficient than performing a matched analysis on the resulting data, particularly when the total number of communities is small and the matching is judged as relatively ineffective.

The research concerning this question has naturally focused on testing the effect of intervention. However, a secondary objective of many community intervention trials is to investigate the effect of individual‐level risk factors on one or more outcome variables. Focusing on the case of a continuous outcome variable, we show that the practice of performing an unmatched analysis on data arising from a matched‐pair design can lead to bias in the estimated regression coefficient, and a corresponding test of significance which is overly liberal. However, for large‐scale community intervention trials, which typically recruit a relatively small number of large clusters, such an analysis will generally be both valid and efficient.

We also consider other approaches to testing the effect of an individual‐level risk factor in a matched‐pair cluster randomization design, including a generalized linear model approach that preserves the matching, a two‐stage cluster‐level analysis, and an approach based on generalized estimating equations. Copyright © 2006 John Wiley & Sons, Ltd.
Training of the next generation of biostatisticians: a call to action in the U.S.
Authors: DeMets David L. , Stormo Gary , Boehnke Michael , Louis Thomas A. , Taylor Jeremy , Dixon Dennis
Published: August 2006

Two workshops (2001, 2003) were held by the National Institutes of Health (NIH) to examine the need to train more biostatisticians in the U.S. to meet the increasing opportunities in the biomedical research enterprise. The supply of new PhD graduates in biostatistics in the U.S. has been relatively steady for the past two decades while the demand has increased dramatically. These workshops concluded that a renewed effort must be made in the U.S., led in part by the NIH, to add to and expand the existing training programs to increase the supply. This article summarizes those two workshops and their recommendations. Some progress has been made through a new biostatistics training program with emphasis in bioinformatics sponsored by the National Institute of General Medical Sciences (NIGMS). Copyright © 2006 John Wiley & Sons, Ltd.
Covariates‐dependent confidence intervals for the difference or ratio of two median survival times
Authors: Chen Yuh‐Ing , Chang Yu‐Mei
Published: August 2006

In this paper, we are concerned with the estimation of the discrepancy between two treatments when right‐censored survival data are accompanied with covariates. Conditional confidence intervals given the available covariates are constructed for the difference between or ratio of two median survival times under the unstratified and stratified Cox proportional hazards models, respectively. The proposed confidence intervals provide the information about the difference in survivorship for patients with common covariates but in different treatments. The results of a simulation study investigation of the coverage probability and expected length of the confidence intervals suggest the one designed for the stratified Cox model when data fit reasonably with the model. When the stratified Cox model is not feasible, however, the one designed for the unstratified Cox model is recommended. The use of the confidence intervals is finally illustrated with a HIV+ data set. Copyright © 2006 John Wiley & Sons, Ltd.
Confidence intervals for predictive values with an emphasis to case–control studies
Authors: Mercaldo Nathaniel D. , Lau Kit F. , Zhou Xiao H.
Published: August 2006

The accuracy of a binary‐scale diagnostic test can be represented by sensitivity (Se), specificity (Sp) and positive and negative predictive values (PPV and NPV). Although Se and Sp measure the intrinsic accuracy of a diagnostic test that does not depend on the prevalence rate, they do not provide information on the diagnostic accuracy of a particular patient. To obtain this information we need to use PPV and NPV. Since PPV and NPV are functions of both the accuracy of the test and the prevalence of the disease, constructing their confidence intervals for a particular patient is not straightforward. In this paper, a novel method for the estimation of PPV and NPV, as well as their confidence intervals, is developed. For both predictive values, standard, adjusted and their logit transformed‐based confidence intervals are compared using coverage probabilities and interval lengths in a simulation study. These methods are then applied to two case–control studies: a diagnostic test assessing the ability of the e4 allele of the apolipoprotein E gene (ApoE.e4) on distinguishing patients with late‐onset Alzheimer's disease (AD) and a prognostic test assessing the predictive ability of a 70‐gene signature on breast cancer metastasis. Copyright © 2006 John Wiley & Sons, Ltd.
Proportional odds logistic regression—effective means of dealing with limited uncertainty in dichotomizing clinical outcomes
Authors: Valenta Zdenek , Pitha Jan , Poledne Rudolf
Published: August 2006

Classifying a measurable clinical outcome as a dichotomous variable often involves difficulty with borderline cases that could fairly be assigned either of the two binary class memberships. In such situations the indicated class membership is often highly subjective and subject to, for instance, a measurement error. In other situations the intermediate level of a three‐level ordinal factor may sometimes be explicitly reserved for cases which could likely belong to either of the two binary classes. Such indefinite readings are often eliminated from the statistical analysis. In this article we review conceptual and methodological aspects of employing proportional odds logistic regression for a three level ordinal factor as a suitable alternative to ordinary logistic regression when dealing with limited uncertainty in classifying clinical outcome as a binary variable. Copyright © 2006 John Wiley & Sons, Ltd.
A deficiency of the odds ratio as a measure of effect size
Authors: Newcombe Robert G.
Published: August 2006

The odds ratio is probably the most widely used measure of association for binary variables. It has many well‐recognized advantages and disadvantages vis‐à‐vis the risk ratio. We demonstrate that for chained or conditional probabilities, odds ratios can behave paradoxically, by failing to show a reinforcement effect that is expressed very clearly when risk ratios are used. Copyright © 2006 John Wiley & Sons, Ltd.
Current status of microplasma research
Authors: Tachibana Kunihide
Published: August 2006

Microscale plasmas of micrometer to millimeter range have been attracting much attention in recent years. Those microplasmas generally operate at high‐pressure regions, including atmospheric pressure, and exhibit characteristics that differ from traditional plasmas at lower pressure regions in their plasma parameters and other parameters originating from their small dimensions. When those characteristics are well combined with the inherent properties of plasmas as reactive, light‐emissive and conductive/dielectric media, there appear a variety of potential applications for nano‐material syntheses, micromachining tools, microchemical analyses, photonic devices and biomaterial processing. In this article, the current status and perspective of microplasma research are reviewed from the viewpoints of plasma generation, diagnostics/simulations and new applications. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Cathode technologies for field emission displays
Authors: Nagao Masayoshi
Published: August 2006

Technologies for the cathode substrate side of field emission displays (FEDs) are briefly described. In addition to electron emitter technologies, evaluation techniques and ways to improve the emission of field emitters are described in detail because these technologies are important for developing practical applications. FEDs will be commercially available within one or two years, and therefore the next generation FEDs beyond these are discussed. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Observation of atmospheric electricity variation signals during underground seismic wave propagation
Authors: Okubo Kan , Sato Shinya , Ishii Takao , Takeuchi Nobunao
Published: August 2006

We have installed an underground electromagnetic observation room in the Hosokura mine in Miyagi Prefecture (Hosokura observation room) to observe the variation in atmospheric electromagnetic signals. In this room, we have set up a large plate electrode to observe signal variation of atmospheric electricity. With this, we have observed co‐seismic electromagnetic phenomena. During the two medium earthquakes that occurred on 27 and 29 February 2004, we observed clear co‐seismic signals in the plate electrode potential variation in the room. A model of the appearance of these signals is examined to explain the observed data. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Local structures and electronic structures of HfON thin films: x‐ray absorption fine structure study and first‐principles calculations
Authors: Kim Sung Kwan , Kim Yangsoo , No Kwangsoo
Published: August 2006

The local structures of HfON thin films were analyzed using an extended x‐ray absorption fine structure (EXAFS) study of the Hf L3‐edge and first‐principles calculations. Depending on their composition and atomic configurations, Hf4O5N2 [coordination number (CN): 6.25], Hf4O2N4 (CN: 5.5) and Hf4O2N4 (CN: 5.0) were suggested as the local structures of HfON thin films. Using the suggested local structures, the electronic structures of HfON thin films were calculated. The variations of the valence band were analyzed with the film composition and compared with the experimental valence band. The optical band gaps of HfON thin films were compared with the calculated values. The transition rate for the optical absorption was suggested as another reason for the band gap difference. Copyright © 2006 John Wiley & Sons, Ltd.
Why American business demands twenty‐first century skills: An industry perspective
Authors: Bruett Karen
Published: August 2006

As a major American employer and a company at the forefront of technology, Dell recognizes the demands of the modern workforce and promotes twenty‐first‐century learning in schools.
Why the American public supports twenty‐first century learning
Authors: Sacconaghi Michele
Published: August 2006

Results from a national opinion survey show broad support for twenty‐first century learning in the form of “basics‐plus” education.
Why America's disadvantaged communities need twenty‐first century learning
Authors: Wilson Blenda J.
Published: August 2006

The nation's achievement gap must be examined within the context of the increasing economic demand for higher‐level skills.
Establishing the R&D agenda for twenty‐first century learning
Authors: Kay Ken , Honey Margaret
Published: August 2006

Infusing twenty‐first century skills into American education requires a detailed research and development plan for teaching, professional development, and assessment significant to these skills.
Twenty‐first century learning in afterschool
Authors: Schwarz Eric , Stolow David
Published: August 2006

Afterschool represents a vast opportunity to reimagine education, building twenty‐first century skills among students beyond the traditional six‐hour school day.
Twenty‐first century learning in schools: A case study of New Technology High School in Napa, California
Authors: Pearlman Bob
Published: August 2006

New Technology High School is an exemplary twenty‐first century learning school, employing project‐ and problem‐based learning and outcomes‐based assessment.
Twenty‐first century learning in school systems: The case of the Metropolitan School District of Lawrence Township, Indianapolis, Indiana
Authors: Capuano Marcia , Knoderer Troy
Published: August 2006

Indianapolis's school district is pioneering a systemic approach to twenty‐first century learning with digital age teacher training and the use of data and technology.
Twenty‐first century learning in states: The case of the Massachusetts educational system
Authors: Driscoll David P.
Published: August 2006

Exemplary efforts at twenty‐first century learning in Massachusetts hold promise for overcoming persistent educational challenges, including high school dropouts and static schools.
Twenty‐first century learning after school: The case of 4‐H
Authors: Kress Cathann
Published: August 2006

The “Learn by Doing” philosophy of 4‐H is an example, now more than one hundred years old, of how out‐of‐school learning programs have been used effectively to develop advanced skills among youth.
Twenty‐first century learning after school: The case of Junior Achievement Worldwide
Authors: Box John M.
Published: August 2006

Junior Achievement has begun to incorporate twenty‐first century skills into its business and entrepreneurship curriculum for youth in its K–12 school and after‐school programs.
Twenty‐first century learning for teachers: Helping educators bring new skills into the classroom
Authors: Wilson John I.
Published: August 2006

For twenty‐first century learning to take hold in schools, teachers must be empowered with the training and infrastructure necessary to incorporate new skills into the classroom.
Twenty‐first century skills for students: Hands‐on learning after school builds school and life success
Authors: Cabral Leide
Published: August 2006

A range of real‐world projects after school in data analysis, writing, problem solving, and oral communication helps an immigrant girl fulfill her father's promise of a good education for a better life.
Synthesis, Crystal Structure and Characterization of the Barium Zinc Tellurate Disilicate: Ba3Zn6[TeO6][Si2O7]2
Authors: Jiang Hai‐Long , Mao Jiang‐Gao
Published: August 2006

The new barium zinc(II) tellurate disilicate Ba3Zn6[TeO6][Si2O7]2 was synthesized by the high temperature solid state reaction of BaCO3, ZnO, and SiO2 with TeO3·H2O in a molar ratio of 3:6:4:1 in an evacuated silica tube at 820 °C. Its structure was established by single‐crystal X‐ray diffraction. Ba3Zn6[TeO6][Si2O7]2 crystallizes in the monoclinic system, space group C2/m (no. 12), with cell parameters of a = 15.975(5), b = 11.505(4), c = 5.142(2) Å, β = 107.437(5)°, V = 901.7(5) Å3, and Z = 2. The structure of Ba3Zn6[TeO6][Si2O7]2 is composed of two types of zinc oxide polyhedra ([ZnO4] tetrahedra and [ZnO6] octahedra), [TeO6] octahedra, disilicate group [Si2O7], [BaO6] and [BaO7] polyhedra. It can be described as a three‐dimensional anionic network of {Zn6[TeO6][Si2O7]2}6−, which is built from one‐dimensional chains of [Zn6TeO18]18− anion interconnected by disilicate [Si2O7]6− groups with the barium cations located at the six‐membered apertures of the above‐mentioned anionic network.