bluuebunny/crossref_metadata_2025 huggingface dataset:
Bayesian methods for generalized linear models with covariates missing at random
Authors: Ibrahim Joseph G. , Chen Ming‐Hui , Lipsitz Stuart R.
Published: June 2006

The authors propose methods for Bayesian inference for generalized linear models with missing covariate data. They specify a parametric distribution for the covariates that is written as a sequence of one‐dimensional conditional distributions. They propose an informative class of joint prior distributions for the regression coefficients and the parameters arising from the covariate distributions. They examine the properties of the proposed prior and resulting posterior distributions. They also present a Bayesian criterion for comparing various models, and a calibration is derived for it. A detailed simulation is conducted and two real data sets are examined to demonstrate the methodology.
Highs and lows: Some properties of the extremes of a diffusion and applications in finance
Authors: Mcleish Donald L.
Published: June 2006

Observations on security prices, currency exchange rates, interest rates, and other financial time series usually include not only an open and close, but also a high and low price for the period. For Brown‐ian motion and certain diffusion processes, the information on high and low prices is of considerable value, particularly for estimating volatility, correlations between processes, and in the pricing of look‐back and barrier options. For pricing more general derivatives, this information is useful to the extent that change in volatility is an important ingredient in the price. The author gives a simple geometric device for generating the extremes of Brownian motion, and geometric Brownian motion; he then uses these extremes in the estimation of the volatility of the processes and to study survivorship bias.
Covariates in multipath change‐point problems: Modelling and consistency of the MLE
Authors: Asgharian Masoud , Wolfson David B.
Published: June 2006

Although the single‐path change‐point problem has been extensively treated in the statistical literature, its multipath counterpart has largely been ignored. In the multipath change‐point setting, it is often of interest to assess the impact of covariates on the change point itself as well as on the parameters before and after the change point. This paper is concerned only with the inclusion of covariates in the change‐point distribution. This is achieved through the hazard of change. Maximum likelihood estimation is discussed and consistency of the maximum likelihood estimators established.
Improved log‐linear model estimators of abundance in capture‐recapture experiments
Authors: Rivest Louis‐Paul , Lévesque Tina
Published: June 2006

The authors review log‐linear models for estimating the size of a closed population and propose a new log‐linear estimator for experiments having between animal heterogeneity and a behavioral response. They give a general formula for evaluating the asymptotic biases of estimators of abundance derived from log‐linear models. They propose simple frequency modifications for reducing these asymptotic biases and investigate the modifications in a Monte Carlo experiment which reveals that they reduce both the bias and the mean squared error of abundance estimators.
Estimation and selection procedures in regression: An L1 approach
Authors: Hengartner Nicolas , Wegkamp Marten
Published: June 2006

The authors consider the problem of estimating a regression function go involving several variables by the closest functional element of a prescribed class G that is closest to it in the L1 norm. They propose a new estimator ĝ based on independent observations and give explicit finite sample bounds for the L1distance between ĝg and go. They apply their estimation procedure to the problem of selecting the smoothing parameter in nonparametric regression.
A semi‐Markov model for binary longitudinal responses subject to misclassification
Authors: Rosychuk Rhonda J. , Thompson Mary E.
Published: June 2006

The authors propose a two‐state continuous‐time semi‐Markov model for an unobservable alternating binary process. Another process is observed at discrete time points that may misclassify the true state of the process of interest. To estimate the model's parameters, the authors propose a minimum Pearson chi‐square type estimating approach based on approximated joint probabilities when the true process is in equilibrium. Three consecutive observations are required to have sufficient degrees of freedom to perform estimation. The methodology is demonstrated on parasitic infection data with exponential and gamma sojourn time distributions.
Using adaptive weighted least squares to reduce the lengths of confidence intervals
Authors: O'Gorman Thomas W.
Published: June 2006

The author proposes an adaptive method which produces confidence intervals that are often narrower than those obtained by the traditional procedures. The proposed methods use both a weighted least squares approach to reduce the length of the confidence interval and a permutation technique to insure that its coverage probability is near the nominal level. The author reports simulations comparing the adaptive intervals to the traditional ones for the difference between two population means, for the slope in a simple linear regression, and for the slope in a multiple linear regression having two correlated exogenous variables. He is led to recommend adaptive intervals for sample sizes superior to 40 when the error distribution is not known to be Gaussian.
Robust linear discriminant analysis using S‐estimators
Authors: Croux Christophe , Dehon Catherine
Published: June 2006

The authors consider a robust linear discriminant function based on high breakdown location and covariance matrix estimators. They derive influence functions for the estimators of the parameters of the discriminant function and for the associated classification error. The most B‐robust estimator is determined within the class of multivariate S‐estimators. This estimator, which minimizes the maximal influence that an outlier can have on the classification error, is also the most B‐robust location S‐estimator. A comparison of the most B‐robust estimator with the more familiar biweight S‐estimator is made.
Exact short poisson confidence intervals
Authors: Kabaila Paul , Byrne John
Published: June 2006

The authors propose a new method for constructing a confidence interval for the expectation θ of a Poisson random variable. The interval they obtain cannot be shortened without the infimum over θ of the coverage probability falling below 1 ‐ α. In addition, the endpoints of the interval are strictly increasing functions of the observed variable. An easy‐to‐program algorithm is provided for computing this interval.
Detection of patterns in noisy time series
Authors: Tingley M. A. , Mclean L.
Published: June 2006

In the context of a research project in ergonomy, myoelectric signals monitored over two to three hour periods gave rise to long noisy time series, which were smoothed using running medians. Tests developed by the authors show that the patterns displayed by the smoothed time series are not artifacts of smoothed white noise. Indeed, the smoothed series show amplitude fluctuations and short‐term correlations which are larger than those obtained by applying running medians to independent, identically distributed data. The key idea is that of reduction of data to binary signals.
Robust sequential designs for nonlinear regression
Authors: Sinha Sanjoy , Wiens Douglas P.
Published: June 2006

The authors introduce the formal notion of an approximately specified nonlinear regression model and investigate sequential design methodologies when the fitted model is possibly of an incorrect parametric form. They present small‐sample simulation studies which indicate that their new designs can be very successful, relative to some common competitors, in reducing mean squared error due to model misspecifi‐cation and to heteroscedastic variation. Their simulations also suggest that standard normal‐theory inference procedures remain approximately valid under the sequential sampling schemes. The methods are illustrated both by simulation and in an example using data from an experiment described in the chemical engineering literature.
Penalized likelihood regression: General formulation and efficient approximation
Authors: Gu Chong , Kim Young‐Ju
Published: June 2006

The authors consider a formulation of penalized likelihood regression that is sufficiently general to cover canonical and noncanonical links for exponential families as well as accelerated life models with censored survival data. They present an asymptotic analysis of convergence rates to justify a simple approach to the lower‐dimensional approximation of the estimates. Such an approximation allows for much faster numerical calculation, paving the way to the development of algorithms that scale well with large data sets.
Monte carlo approximation to edgeworth expansions
Authors: Hall Peter , Martin Michael A. , Sun Shan
Published: June 2006

Since the 1930s, empirical Edgeworth expansions have been employed to develop techniques for approximate, nonparametric statistical inference. The introduction of bootstrap methods has increased the potential usefulness of Edgeworth approximations. In particular, a recent paper by Lee & Young introduced a novel approach to approximating bootstrap distribution functions, using first an empirical Edgeworth expansion and then a more traditional bootstrap approximation to the remainder. In principle, either direct calculation or computer algebra could be used to compute the Edgeworth component, but both methods would often be difficult to implement in practice, not least because of the sheer algebraic complexity of a general Edgeworth expansion. In the present paper we show that a simple but nonstandard Monte Carlo technique is a competitive alternative. It exploits properties of Edgeworth expansions, in particular their parity and the degrees of their polynomial terms, to develop particularly accurate approximations.
Multiple roots of estimating functions
Authors: Small Christopher G. , Yang Zejiang
Published: June 2006

Estimating functions can have multiple roots. In such cases, the statistician must choose among the roots to estimate the parameter. Standard asymptotic theory shows that in a wide variety of cases, there exists a unique consistent root, and that this root will lie asymptotically close to other consistent (possibly inefficient) estimators for the parameter. For this reason, attention has largely focused on the problem of selecting this root and determining its approximate asymptotic distribution. In this paper, however, we concentrate on the exact distribution of the roots as a random set. In particular, we propose the use of higher‐order root intensity functions as a tool for examining the properties of the roots and determining their most problematic features. The use of root intensity functions of first and second order is illustrated by application to the score function for the Cauchy location model.
Experimental investigation of the SCR of NOx in a simulated moving bed reactor
Authors: Fissore Davide , Tejedor Diego Garran , Barresi Antonello A.
Published: June 2006

The experimental investigation of the Selective Catalytic Reduction (SCR) of NOx with NH3 in a Simulated Moving Bed (SMB) reactor realized by means of a network of three catalyst beds with periodical variation of the feed position is dealt with. The influence of the main operating parameters, namely, the inlet flow rate, the switching frequency, and the working temperature, has been investigated, as well as the responses of this device to disturbances in the feeding. A simple one‐dimensional (1‐D) model has been validated by means of the comparison with the experimental results. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Crystallization and melting behavior of blends comprising poly(3‐hydroxy butyrate‐co‐3‐hydroxy valerate) and poly(ethylene oxide)
Authors: Tan S. M. , Ismail J. , Kummerlöwe C. , Kammer H. W.
Published: June 2006

Blends of poly(3‐hydroxy butyrate‐co‐3‐hydroxy valerate) (PHBV) and poly(ethylene oxide) (PEO) were prepared by casting from chloroform solutions. Crystallization kinetics and melting behavior of blends have been studied by differential scanning calorimetry and optical polarizing microscopy. Experimental results reveal that the constituents are miscible in the amorphous state. They form separated crystal structures in the solid state. Crystallization behavior of the blends was studied under isothermal and nonisothermal conditions. Owing to the large difference in melting temperatures, the constituents crystallize consecutively in blends; however, the process is affected by the respective second component. PHBV crystallizes from the amorphous mixture of the constituents, at temperatures where the PEO remains in the molten state. PEO, on the other hand, is surrounded during its crystallization process by crystalline PHBV regions. The degree of crystallinity in the blends stays constant for PHBV and decreases slightly for PEO, with ascending PHBV content. The rate of crystallization of PHBV decreases in blends as compared to the neat polymer. The opposite behavior is observed for PEO. Nonisothermal crystallization is discussed in terms of a quasi‐isothermal approach. Qualitatively, the results show the same tendencies as under isothermal conditions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2776–2783, 2006
Studies on the effects of the enzymatic treatment on silk fine powder
Authors: Xu Weilin , Ke Guizhen , Peng Xuqiang
Published: June 2006

In this study, the silk treated by steam explosion was pulverized into fine powder with a mean particle size of 1.829 μm, then the feasibility of the application of the protease treatment to produce finer and more uniform silk powder was investigated. The results indicated that after the enzymatic treatment, the mean diameter of the silk powder was reduced from 1.829 to 1.546 μm and the equivalent diameter distribution became more concentrated; thus, the uniformity of the particles was improved. The infrared spectra analysis demonstrated that the silk powder remained the β‐sheet crystalline structure. X‐ray diffraction analysis showed the crystallinity of the polished silk powder was very slightly strengthened. It was found that the treatment reduced some polar amino acid in the sericin; however, the composition of the kinds of the amino acids did not change. In addition, the hot water‐solubility and moisture regain of the polished silk powder declined very slightly. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2967–2971, 2006
Thermally stimulated depolarization current behavior of polyethylene/poly(vinyl acetate) blends: Effect of blending
Authors: Choure Churaman , Keller J. M. , Bajpai R.
Published: June 2006

Thermally stimulated depolarization currents (TSDCs) were investigated in polyethylene/poly(vinyl acetate) blends as a function of the polarizing temperature, applied field, and poly(vinyl acetate) weight percentage in the blend. The magnitude of the TSDC peak current decreased and the peak current position shifted toward the lower temperature side as the poly(vinyl acetate) weight percentage in the blends was increased. The tendency of the current toward anomalous behavior (flowing in the same direction as the charging current) also increased. It was concluded that blending with poly(vinyl acetate) modified the polyethylene morphology such that the amorphous part was increased. The carriers with mobility enhanced by hopping centers due to the CO group in the amorphous part were localized largely in shallow traps. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3040–3045, 2006
The effect of process variables on the morphology and release characteristics of protein‐loaded PLGA particles
Authors: Yushu Huang , Venkatraman Subbu
Published: June 2006

Poly(lactide‐co‐glycolide) (PLGA 75 : 25), IV 0.94 dL/g was chosen as the matrix of the microparticles. Bovine serum albumin (BSA) (Fraction V) as the model drug was incorporated in the microparticles by a W/O/W emulsification and solvent evaporation technique. The effect of the various preparation parameters on particle morphology, drug loading efficiency, and drug release profiles of the resultant microparticles were examined. Particle size varied from 5 to 60 μm. The final morphology of the microparticles varied dramatically with preparation variables such as equipment used to produce the primary emulsion (W1/O) and the water‐to‐oil ratio (W1/O) in the primary emulsion. In general, the viscosity of the primary emulsion had a significant effect on the porosity of particles produced. The release of BSA showed a strong relationship with the preparation parameters of microparticles, partly due to the morphological effects. For example, microparticles made from the vortex mixer that was used to disperse inner aqueous phase (W1) to oil phase (O) showed a lower burst effect than that made from the homogenizer because of its better surface morphology. W1/O ratio, speed of dispersing the primary emulsion into W2, PLGA concentration, and different matrix materials also affected the drug release profiles. In all the samples studied here, only diffusion‐controlled release was observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3053–3061, 2006
Wissenstransfer auf dem Prüfstand. Europäische Mediziner im Kampf gegen die Pest von Moskau 1771
Authors: Renner Andreas
Published: June 2006

Foreign knowledge being tested: European physicians fighting the Moscow plague of 1771. – The transfer of Western medicine to Russia increased significantly in the Eighteenth century. Foreign doctors were employed, their writings translated, their education standards copied. But who regarded that knowledge as superior and why? Taking the Moscow Plague of 1771 as a case study, this article examines the crucial role foreign and Russian medical practitioners played during the epidemic. It argues that especially those ideas and practices that were useful for social control filtered into politics and public discourse, but failed to convince the majority of the population.
Rank deficiency in superconvergent patch recovery techniques with 4‐node quadrilateral elements
Authors: Yue Z. , Robbins D. H.
Published: June 2006

The linear systems of equations generated by the Superconvergent Patch Recovery technique (Int. J. Numer. Methods Eng. 1992; 33:1331–1382; Comput. Methods Appl. Mech. Eng. 1992; 101:207–224) can exhibit rank deficiency under certain purely geometric conditions. The rank deficiency problem can be corrected simply and efficiently by utilizing a local rotated co‐ordinate system. This rotated SPR procedure is easily automated and adds robustness to automatic adaptive solution methods. Copyright © 2006 John Wiley & Sons, Ltd.
Collocation methods based on radial basis functions for solving stochastic Poisson problems
Authors: Chantasiriwan Somchart
Published: June 2006

Collocation methods based on radial basis functions can be used to provide accurate solutions to deterministic problems. For stochastic problems, accurate solutions may not be desirable if they are too sensitive to random inputs. In this paper, four methods are used to solve stochastic Poisson problems by expressing solutions in terms of source terms and boundary conditions. Comparison among the methods reveals that the method based on fundamental solutions performs better than other methods. Copyright © 2006 John Wiley & Sons, Ltd.
An amylase/cre transgene marks the whole endoderm but the primordia of liver and ventral pancreas
Authors: Kockel Liliana , Strom Alessandra , Delacour Alexandra , Népote Virginie , Hagenbüchle Otto , Wellauer Peter K. , Herrera Pedro L.
Published: June 2006

Mice bearing a Cre‐encoding transgene driven by a compound [SV40 small t antigen/mouseα‐amylase‐2] promoter expressed the recombinase at early developmental stages broadly in the embryonic endoderm before the pancreas and lungs begin to outgrow, but not in other germ layers, as determined indirectly by β‐galactosidase and YFP reporter activity, indicating that the transgene is in fact an endodermic marker. Interestingly, the liver and ventral pancreas were excluded from this expression pattern, denoting that the chimerical α‐amylase‐2 promoter was not active in the anterior leading edge of the endoderm (the presumptive region from which liver and ventral pancreas form). These transgenics thus confirm, among other findings, that dorsal and ventral pancreatic primordia have different intrinsic transcriptional capabilities. In conclusion, we have generated a new transgenic mouse that should be useful to target endoderm at early stages, without affecting the liver or ventral pancreas before embryonic day E12.5. genesis 44:287–296, 2006. © 2006 Wiley‐Liss, Inc.
Development of NbTi superconducting strands and cables for the field winding of a 200‐MW‐class high‐energy‐density superconducting generator
Authors: Miyashita Katsumi , Sato Hiroyuki , Arika Mitsuhiro , Takahashi Ryukichi
Published: June 2006

The NbTi superconducting strands and cables for the field winding of the 200‐MW‐class high‐energy‐density‐type superconducting generator are developed. They are composed of Cu/Cu‐10wt%Ni/Nb‐46.5wt%Ti superconducting strands and the 10‐kA (at 5 T)‐class 9‐strand compacted cables. The diameter of strands is 1.33 mm, and the 9‐strand compacted cables are 2.4 mm thick and 6.0 mm wide. In order to produce high‐current‐density NbTi strands, we made strands under controlled aging heat treatments, the total and final strains, and the strains between heat treatments, by using large‐scale extruder. Moreover, in order to produce high‐stability and low‐AC‐loss NbTi strands and cables, the matrix ratio of strands and the cross sections of strands are optimized. The current density of NbTi filaments for the four‐time‐aging manufactured 1.33‐mm‐diameter strands was JC=3150 A/mm2 at 5 T, 1150 A/mm2 at 8 T. The critical current of the 9‐strand compacted cable is 10.7 kA at 5 T. The AC losses of the final compacted cables are less than 100 kW/m3 at 5 T, 5 T/s, that is, decreased to less than half of the target of the AC loss value (< $\ 200 \hbox{ kW/m}^{3}$ at 5 T, 5 T/s). Compared with the strand (Cu ratio 1.77), the minimum quench energy (MQE) of the strand (Cu ratio>2) increased about 40% at the operation mode current of the superconducting generator. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(3): 24– 31, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20266
Effective sticking coefficient measurement of radicals for a‐SIN:H film growth in plasma CVD
Authors: Fujikake Shinji , Narita Masataka , Ichikawa Yukimi
Published: June 2006

The reaction coefficients of radicals on the growing surface of hydrogenated amorphous silicon nitride (a‐SiN:H) were studied by applying Monte Carlo simulation. These a‐SiN:H films were deposited on trench‐patterned silicon wafers using two kinds of gas mixture, SiH4−NH3 and SiH4−N2, and then measured for their film thickness profiles and composition on the trench wall. The derived total loss coefficient, β, of radicals was estimated from comparison between the experimental results and the simulation. On the basis of these results, the main radicals during depositions will be discussed. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(3): 9– 15, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20343
High‐speed imaging of laser intensity distribution using an acousto‐optic deflector
Authors: Fukuchi Tetsuo , Nemoto Koshichi , Matsumoto Kouji
Published: June 2006

An acousto‐optic laser deflector was used to image the intensity distribution of a continuous wave laser of microsecond order. Undeflected light was blocked while the deflected light was directed to a CCD camera, which allowed imaging of the incident laser intensity distribution of microsecond order. Experiments using a test pattern showed that there was no distortion in the deflected image. The resolution limit, estimated from diffractive effects, was about 0.2 mrad. Using this method of high‐speed imaging, density variations accompanying laser‐induced breakdown in air were visualized by shadowgraphy and interferometry. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(3): 55–61, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20386
Modification of TLR‐induced activation of human dendritic cells by type I IFN: synergistic interaction with TLR4 but not TLR3 agonists
Authors: Walker Josef , Tough David F.
Published: June 2006

Upon detection of direct and indirect signs of infection, dendritic cells (DC) undergo functional changes that modify their ability to elicit immune responses. Type I interferon (IFN‐α/β), which includes a large family of closely related infection‐inducible cytokines, represents one indirect signal that can act as a DC stimulus. We have investigated the ability of IFN‐α/β subtypes to affect DC function and to influence DC responses to Toll‐like receptor (TLR) agonists (i.e., direct infection‐associated signals). Subtle differences were observed among 15 subtypes of IFN‐α/β in the ability to stimulate expression of maturation markers and chemokines by human monocyte‐derived DC, with IFN‐ω being the most unique in its effects. Pre‐treatment with IFN‐α/β did not alter the ability of DC to mature in response to subsequent contact with TLR agonists, but did modulate their secretion of chemokines. Conversely, IFN‐α/β was shown to act synergistically with TLR4 but not TLR3 agonists for the induction of maturation and chemokine production when DC were exposed to IFN‐α/β and TLR ligands simultaneously. Taken together, these results indicate a complex role for IFN‐α/β in regulating DC function during the course an infection, which varies according to IFN‐α/β subtype and the timing of exposure to other stimuli.
In Situ Synthesis, Characterization of SiPMo‐X, and Different Catalytic Properties of SiPMo‐X and SiPW‐X
Authors: Shi Chunfeng , Wang Runwei , Zhu Guangshan , Qiu Shilun , Long Jun
Published: June 2006

SBA‐15 frameworks with encapsulated Keggin type heteropolyacids (HPAs) were synthesized in situ under strongly acidic conditions (pH < 0). During the hydrolysis of tetraethyl orthosilicate (TEOS), a P‐ and a Mo source were added into the initial sol–gel system to form Keggin type HPAs. The texture of the final products was studied by the N2 adsorption–desorption isotherms and transmission electron microscopy (TEM), and their structure was systematically characterized by X‐ray diffraction (XRD), UV/Vis diffuse reflectance‐ (DRS), infrared‐ (IR), and 31P magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy. Characterization results suggest that the samples show very ordered hexagonal mesostructure, and the HPAs that are incorporated into the framework of meso‐silica are insoluble during catalysis. Results of catalytic tests indicate that the materials demonstrated catalytic activity comparable with or even surpassing those of the bulk HPAs in catalytic tests implementing chemical reactions of bulky molecules (1,3,5‐triisopropylbenzene cracking, esterification of benzoic acid with tert‐butyl alcohol, and 2,3,6‐trimethylphenol hydroxylation with H2O2). Additionally, some other properties, such as easy separation and stability when recycled, ensure their potential applications in the chemical industries. Here, we report not only the in situ synthesis and characterization of SiPMo‐X, but also the difference in the catalytic properties of SiPMo‐X and SiPW‐X. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Interval estimation for log‐normal mean with applications to water quality
Authors: El‐Shaarawi Abdel H. , Lin Jing
Published: June 2006

Large samples based confidence interval is frequently used by environmental scientists as an approximate data summary about the log‐normal regression mean. It has been shown by simulation that the coverage probability of such an interval is below the intended nominal level for small samples. To overcome this difficulty, a complicated small sample corrected interval has been recently proposed in the literature which substantially improves the coverage probability. In this paper, similar improvement are obtained by simply replacing the quantile of the normal distribution by the appropriate quantile of Student t distribution as will be demonstrated in this paper by simulation. The advantage of our proposed interval is its simplicity and thus will be easier to use in applications. As an illustration, we use the method to study the relationship between the flow and concentration of total phosphorous (TP) at four upstream/downstream sampling locations on the Fraser River of British Columbia. Our interests in developing intervals for the mean TP level at each location as well as the ratio of the mean at a downstream location to that at an upstream location. Such study is important in tracing the evolution of pollutants in an ecosystem and thus in setting policies for pollution control. Copyright © 2006 John Wiley & Sons, Ltd.
Numerical predictions of flow and thermal fields in an enclosure with two periodically moving walls
Authors: Cheng Chin‐Hsiang , Hung Kuo‐Shu
Published: June 2006

Numerical predictions of transient flow and thermal fields in a rectangular enclosure with two periodically moving vertical walls are presented. The combined influence of the movement of the walls and the buoyancy as well on the flow pattern and heat transfer performance is evaluated. The compressible‐flow model is adopted, and governing equations are expressed in integral form and discretized on the moving grids, which deform in resonance with the walls to accommodate the variation in the volume of the enclosure. A two‐stage pressure‐correction scheme is applied for simultaneously determining the distributions of absolute pressure, density, temperature, and velocity of the compressible flow field in the enclosure during the periodically stable periods. Effects of the frequency, stroke, and the phase angle of the wall oscillations on the flow are of major concerns in this study. The frequency is ranged between 5 and 25 Hz and the dimensionless strokes (l/H) of the wall are varied from 0.4 to 1.0. Results for Nusselt numbers on the walls as well as the dimensionless input work required to excite the wall oscillation are provided. Copyright © 2006 John Wiley & Sons, Ltd.
Optimal convergence properties of the FETI domain decomposition method
Authors: Maday Y. , Magoulès F.
Published: June 2006

In this paper an original variant of the FETI domain decomposition method is introduced for heterogeneous media. This method uses new absorbing interface conditions in place of the Neumann interface conditions defined in the classical FETI method. The optimal convergence properties of the classical FETI method and of its variant are first demonstrated, both in the case of homogeneous and heterogeneous media. Secondly, novel and efficient absorbing interface conditions, which avoid rigid body motions, are investigated and analysed. Numerical experiments illustrate the dependence of the proposed method upon several parameters, and confirm the robustness and efficiency of this method when equipped with such absorbing interface conditions. Copyright © 2006 John Wiley & Sons, Ltd.
Higher‐order bounded differencing schemes for compressible and incompressible flows
Authors: Ng K. C. , Yusoff M. Z. , Ng E. Y. K.
Published: June 2006

In recent years, three higher‐order (HO) bounded differencing schemes, namely AVLSMART, CUBISTA and HOAB that were derived by adopting the normalized variable formulation (NVF), have been proposed. In this paper, a comparative study is performed on these schemes to assess their numerical accuracy, computational cost as well as iterative convergence property. All the schemes are formulated on the basis of a new dual‐formulation in order to facilitate their implementations on unstructured meshes. Based on the proposed dual‐formulation, the net effective blending factor (NEBF) of a high‐resolution (HR) scheme can now be measured and its relevance on the accuracy and computational cost of a HR scheme is revealed on three test problems: (1) advection of a scalar step‐profile; (2) 2D transonic flow past a circular arc bump; and (3) 3D lid‐driven incompressible cavity flow. Both density‐based and pressure‐based methods are used for the computations of compressible and incompressible flow, respectively. Computed results show that all the schemes produce solutions which are nearly as accurate as the third‐order QUICK scheme; however, without the unphysical oscillations which are commonly inherited from the HO linear differencing scheme. Generally, it is shown that at higher value of NEBF, a HR scheme can attain better accuracy at the expense of computational cost. Copyright © 2006 John Wiley & Sons, Ltd.
A parametric finite‐difference method for shallow sea waves
Authors: Bratsos A. G. , Famelis I. Th. , Prospathopoulos A. M.
Published: June 2006

This paper presents a parametric finite‐difference scheme concerning the numerical solution of the one‐dimensional Boussinesq‐type set of equations, as they were introduced by Peregrine (J. Fluid Mech. 1967; 27(4)) in the case of waves relatively long with small amplitudes in water of varying depth. The proposed method, which can be considered as a generalization of the Crank‐Nickolson method, aims to investigate alternative approaches in order to improve the accuracy of analogous methods known from bibliography. The resulting linear finite‐difference scheme, which is analysed for stability using the Fourier method, has been applied successfully to a problem used by Beji and Battjes (Coastal Eng. 1994; 23: 1–16), giving numerical results which are in good agreement with the corresponding results given by MIKE 21 BW (User Guide. In: MIKE 21, Wave Modelling, User Guide. 2002; 271–392) developed by DHI Software. Copyright © 2006 John Wiley & Sons, Ltd.
Numerical simulation of isothermal nonwetting
Authors: Kuo C.‐W. , Chen J.‐C. , Neitzel G. P.
Published: June 2006

A numerical simulation of isothermal wetting suppression in the presence of shear is considered during which wetting may be prevented when a drop approaches a moving wall. Air is driven into the passage between the solid and liquid surfaces by viscous action, preventing wetting. Silicone‐oil and water drops are investigated for different wall velocities and wall distances. The droplet dimples at the upstream side and bulges at the downstream side when nonwetting occurs. The free‐surface deformation can be enlarged by either increasing the wall velocity or decreasing the wall distance. The low‐viscosity silicone‐oil used in these calculations is much more sensitive to shear wetting suppression than is water, because the Weber number of the silicone‐oil is larger than that of water. Copyright © 2006 John Wiley & Sons, Ltd.
‘Normal counterparts’ of nodal peripheral T‐cell lymphoma
Authors: Rüdiger Thomas , Geissinger Eva , Müller‐Hermelink Hans Konrad
Published: June 2006

Peripheral T‐cell lymphomas (PTCL) have been difficult to classify. A homogeneous principle of classification is still lacking, partly because lymph node compartments containing functionally distinct T‐cell subsets have not been identified. A correlation to differentiated T‐cell subsets, as CD4+ or CD8+ cells as well as cytotoxic populations has not revealed clinically meaningful entities. Upon antigen encounter, mature T‐cells pass through distinct stages characterized by their surface molecule expression. Naïve T‐cells are CD45RA+/CD45R0−/CD27+/CCR7+, however, after antigen contact CD45RA expression is replaced by CD45R0. They differentiate to central memory cells, which retain CD27 and CCR7, or to effector‐memory cells, which loose expression of both molecules depending on the strength of the antigen interaction. Immunohistological analysis of PTCL showed an effector or effector‐memory cell phenotype (CD45RA−/CD45R0+/CD27−) for both angioimmunoblastic T‐cell lymphoma (AILT) and anaplastic large cell lymphoma (ALCL), but different cytotoxic and activation markers expressed by these tumours. A subset of CD4+ PTCL‐not otherwise specified (PTCL‐NOS) may correspond to a central memory cell phenotype (CD45RA−/CD45R0+/CD27+). Thus, a correlation of PTCL to stages of differentiation, rather than to the direction of differentiation, may reveal homogeneous categories. A comparison between the lymphomas and their normal counterparts maycontribute to the understanding of the underlying transformation mechanisms. Copyright © 2006 John Wiley & Sons, Ltd.
Automated measurement of mean wall thickness in the common carotid artery by MRI: A comparison to intima‐media thickness by B‐mode ultrasound
Authors: Underhill Hunter R. , Kerwin William S. , Hatsukami Thomas S. , Yuan Chun
Published: June 2006

Purpose

To determine whether the mean wall thickness (MWT) of the common carotid artery (CCA) measured by MRI is comparable to B‐mode ultrasound (US) measurement of the intima‐media thickness (IMT), an established marker of cardiovascular risk.

Materials and Methods

As part of the two‐year ORION trial, 43 patients with 16–79% stenosis by duplex US underwent high‐resolution MRI and B‐mode US examinations of their carotid arteries. Twenty‐eight carotid arteries were identified as having both sufficient proximal coverage and adequate image quality of the CCA on MRI and a corresponding US. A novel algorithm utilizing statistical shape modeling was developed to automatically detect and measure MWT to within subpixel accuracy. The interrater and interscan reproducibility of the MWT measurement was computed as the root‐mean‐square (RMS) difference. The MWT and IMT measurements were compared via the Pearson correlation coefficient.

Results

The MWT and IMT had a high Pearson correlation coefficient (r = 0.93; P < 0.001). The RMS difference between readers and between scans was 0.01 mm and 0.04 mm, respectively. Our automated algorithm correctly identified the lumen in 28 cases (100%) and the outer‐wall boundary in 26 cases (93%).

Conclusion

Automated measurements of the MWT by MRI are reproducible and have a high correlation with the IMT by B‐mode US. J. Magn. Reson. Imaging 2006. Published 2006 Wiley‐Liss, Inc.
Temporal dynamics of neurite outgrowth promoted by basic fibroblast growth factor in chick ciliary ganglia
Authors: Zamburlin Pollyanna , Gilardino Alessandra , Dalmazzo Simona , Ariano Paolo , Lovisolo Davide
Published: June 2006

Basic fibroblast growth factor (bFGF) is a potent and multifunctional neurotrophic factor that can influence neuronal survival and differentiation. It has been shown to modulate growth and orientation of neuritic processes both in intact organs and in neuronal cultures, with a wide spectrum of effects on different preparations. Here we report that it promotes neurite growth in developing parasympathetic neurons from the chick ciliary ganglion. We have used both organotypic cultures and dissociated neurons, and we have combined assessment of global neurite growth by immunocytochemical techniques with evaluation of dynamic parameters of single neurites via time‐lapse microscopy. We show that laminin, a molecule of the extracellular matrix that has been associated with stimulation of neurite extension, has only a limited and short‐lived effect on neurite outgrowth. In contrast, bFGF can promote global growth of the neuritic network both in whole ganglia and in dissociated cultures for times up to 48 hr, and this effect is related to an increase in the growth rate of single neurites. Moreover, the effect can be observed even in enriched neuronal cultures, pointing to a direct action of bFGF on neurons. © 2006 Wiley‐Liss, Inc.
Factors affecting the meat quality of veal
Authors: Ngapo Tania M , Gariépy Claude
Published: June 2006

Over the last 50 years the veal industry has seen a number of changes, in particularly in production systems with the introduction and acceptance of grain‐fed and heavier calves and the progressive move from individual pens to group housing. Reasons for the changes are multi‐faceted of which two important players are the well‐being of the animal and the public perception of the industry. Regardless of the reasons for the changes, breeders strive to attain veal conforming to the rigorous standards reflecting consumer demands. Consequently a multitude of publications exists on production factors in veal farming. However, many of these reports stop at the ‘farm gate’, or more correctly, the slaughterhouse, where carcass characteristics in particular are assessed. Changes in production systems generally aim to improve feed efficiency and weight gains, but often overlook meat quality aspects which ultimately dictate financial gains. This review aims to summarise the existing and available literature on factors affecting the quality of veal meat. The topics covered include the effects of breed, sex, weight or age, diet composition and dietary treatments, environment and pre‐slaughter handling, and processing factors such as stunning, electrical stimulation, ageing and packaging. Copyright © 2006 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
Xanthate‐Mediated Controlled Radical Polymerization of N‐Vinylcarbazole
Authors: Mori Hideharu , Ookuma Hiroshi , Nakano Shuji , Endo Takeshi
Published: June 2006

Summary: Well‐defined poly(N‐vinylcarbazole) [poly(NVC)] was synthesized by macromolecular design via interchange of the xanthates (MADIX)/reversible addition‐fragmentation chain transfer (RAFT) polymerization. The homopolymers with controlled molecular weights ($\overline M _{\rm n}$ = 3 000–48 000) and low polydispersities indices ($\overline M _{\rm w} /\overline M _{\rm n}$ = 1.15–1.20) were obtained by the polymerization of NVC with AIBN in the presence of O‐ethyl‐S‐(1‐phenylethyl) dithiocarbonate as a xanthate‐type chain transfer agent (CTA). Good control of the polymerization was confirmed by the linear first‐order kinetic plot, the molecular weight controlled by the monomer/CTA molar ratio, linear increase in the molecular weight with the conversion, and the ability to extend the chains by the second addition of the monomer.

Radical polymerization of NVC in the presence of CTA and plot of number‐average molecular weight (circles) and polydispersity (squares) as a function of conversion.

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Radical polymerization of NVC in the presence of CTA and plot of number‐average molecular weight (circles) and polydispersity (squares) as a function of conversion.
Connector Effect in Electroluminescent Properties of Poly(p‐phenylene vinylene) Derivatives Containing Triazole Chromophores
Authors: Chen Shinn‐Horng , Chen Yun
Published: June 2006

Summary: We report the thermal, optical, electrochemical and electroluminescent properties of four polymers P1–P4 consisting of hole‐transporting [1,4‐bis(hexyloxy)‐2,5‐distyrylbenzene;DSB] and electron‐transporting [4‐(4‐(hexyloxy)phenyl)‐3,5‐diphenyl‐4H‐1,2,4‐triazole; TAZ] fluorophores linked by four kinds of connectors: (1) ether spacers, (2) single bonds, (3) 1,4‐phenylenes, and (4) 1,4‐divinylbenzenes. These polymers are soluble in common organic solvents such as chloroform, N‐methylpyrrolidone (NMP) and CH2Cl2CH2Cl2 and exhibit good thermal stability with decomposition temperatures higher than 340 °C. Compounds M1–M3 containing a TAZ or DSB core were employed as a model to study the optical properties of the polymers. The photoluminescence (PL) spectral maxima of P1–P4 in CHCl3 were spread over a wide range, from 453 nm to 501 nm, depending upon the chemical structures of the connectors. In the film state, the PL maxima shifted bathochromically from 464nm to 538 nm, which can be attributed to the formation of excimers. From the optimized semiempirical modified neglect of diatomic overlap (MNDO) calculations, the adjacent benzene rings between DSB and TAZ chromophores in P2 and P3 twist about 81–89° which is significantly different from P4 (circa 0°). The effect of the twisted connector architectures on optical and electrochemical properties for P1–P4 is discussed. The electroluminescences of P1–P4 and corresponding Commission Internationale de l'Eclairage (C.I.E.) coordinates are also depicted to indicate that incorporating different connectors to these polymers changed their color from blue, to green, to the yellow region.

The C.I.E. 1931 diagram of lights emitted from the PLED devices (ITO/PEDOT:PSS/P1–P4/Al).

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The C.I.E. 1931 diagram of lights emitted from the PLED devices (ITO/PEDOT:PSS/P1–P4/Al).
Stabilization of Polymer Bilayers by Introducing Crosslinking at the Interface
Authors: An Narong , Li Yanxia , Yang Yuming , Yu Fusheng , Dong Lisong
Published: June 2006

Summary: Bisphenol A solid epoxy serves as an effective reaction compatibilizer to the bisphenol A polycarbonate (PC)/PMMA bilayer systems. Addition of epoxy to the bottom PMMA layer can retard or even prevent the dewetting of PC films by introducing crosslinking between both components at the interface. This is the first investigation of polymer bilayers stabilized by chemical reactions.

AFM topographic image of a representative dewetting hole.

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AFM topographic image of a representative dewetting hole.
Continuum damage mechanics for hysteresis and fatigue of quasi‐brittle materials and structures
Authors: Desmorat R. , Ragueneau F. , Pham H.
Published: June 2006

For a material exhibiting hysteresis such as quasi‐brittle materials, it is natural to consider that hysteresis and fatigue are related to each other. One shows in the present work that damage, from the continuum damage mechanics point of view, may be seen as the link between both phenomena. One attempts, hence, to set up a unified modelling of hysteresis and damage. Numerical examples are given for concrete and validate the proposed model of internal sliding and friction coupled with damage. The problem of a proper phenomenological modelling of the micro‐defects closure effect leading to a dissymmetric tension/compression response and to stiffness recovery in compression is also addressed. Cyclic and fatigue applications are in mind, and also random fatigue and seismic responses. Copyright © 2006 John Wiley & Sons, Ltd.
Police interview competencies: assessment and associated traits
Authors: De Fruyt Filip , Bockstaele Marc , Taris Ruben , Van Hiel Alain
Published: June 2006

The present study empirically examines the structure of police interview competencies in self‐reports of 230 police investigators suggesting five major underlying dimensions, that is, ‘Careful‐tenacious’, ‘Controlled‐non‐reactive’, ‘Dominant‐insisting’, ‘Communicative’ and ‘Benevolent’. These dimensions discriminate performance in a series of interview vignettes, grouped in terms of type of case (interviewing a suspect, a witness or a victim) and type of suspect. In addition self‐ratings on these dimensions are related to self‐estimated interview effectiveness in the same vignettes. Participants are further administered the NEO PI‐R (Costa, P. T., & McCrae, R. R. (1992). Professional manual: Revised NEO personality inventory (NEO‐PI‐R) and NEO five‐factor‐inventory (NEO‐FFI). Odessa, FL: Psychological Assessment Resources), enabling an examination of the relationship between the competence dimensions and their personality trait building blocks. The implications of this study for the development and coaching of police interview competencies are discussed. Copyright © 2006 John Wiley & Sons, Ltd.