bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation and Verification of Hypotheses in Some Zyskind‐Martin Models with Missing Values
Authors: Oktaba W. , Kornacki A. , Wawrzosek J.
Published: May 2007

Several theorems on estimation and verification of linear hypotheses in some Zyskind‐Martin (ZM) models are given. The assumptions are as follows. Let y = Xβ + e or (y, Xβ, σ2V) be a fixed model where y is a vector of n observations, X is a known matrix nXp with rank r(X) = r ≦ p < n, where p is a number of coordinates of the unknown parameter vector β, e is a random vector of errors with covariance matrix σ2V, where σ2 is unknown scalar parameter, V is a known non‐negative definite matrix such that R(X) ⊂ R(V). Symbol R(A) denotes a vector space generated by columns of matrix A. The expected value of y is Xβ. In this paper four following Zyskind‐Martin (ZM) models are considered: ZMd, ZMa, ZMc and ZMqd (definitions in sec. 1) when vector y y1 y2 involves a vector y1 of m missing values and a vector y2 with (n — m) observed values.

A special transformation of ZM model gives again ZM model (cf. theorem 2.1). Ten properties of actual (ZMa) and complete (ZMc) Zyskind‐Martin models with missing values (cf. theorem 2.2) test functions F are given in (2.11)) are presented.

The third propriety constitutes a generalization of R. A. Fisher's rule from standard model (y, Xβ, σ2I) to ZM model.

Estimation of vector y1 (cf. 3.3) of vector β (cf. th. 3.2) and of scalar σ2 (cf. th. 3.4) in actual ZMa model and in diagonal quasi‐ZM model (ZMqd) are presented. Relation between y̌ 1 and β is given in theorem 3.1. The results of section 2 are illustrated by numerical example in section 4.
A Life Table Regression Analysis for Complex Survey Data
Authors: O'Brien Kevin F. , Suchindran C. M.
Published: May 2007

A methodology for obtaining maximum likelihood estimates of life table regression coefficients from complex survey data is presented. Certain of the issues of writing a likelihood for survey data are presented and discussed.

The proposed methodology includes consideration of the sampling design in any inference by using design based variance estimates for the parameters. An example is given using data from the 1973 United States National Survey of Family Growth.
On the Stochastic Theory of Compartments: The Two‐Compartment and the Mammillary Compartment Systems
Authors: Agrafiotis G. K.
Published: May 2007

A two‐compartment and a mammillary compartment system with arbitrary sojourn time distributions for each of the compartments is analysed in this paper, both with and without input. Several results found earlier by other authors for these systems are generalized and some new results are also added.
Optimum Design in Multivariate Stratified Sampling
Authors: Omule S. A. Y.
Published: May 2007

The procedure of determining the optimum sample size in each stratum in stratified sampling for several variables is expressed and solved as a multistage decision process through dynamic programming. Using data published elsewhere, the dynamic programming approach was shown to give results identical to those obtained by some other already suggested approaches. The advantage is that dynamic programming can more easily handle problems involving several strata and/or variables.
Some Considerations for the R to One Matching Situation
Authors: Somes Grant W.
Published: May 2007

The asymptotic relative efficiency of the R to one matching design is compared to a standard one to one matching design for both continuous and dichotomous data. An additional consideration which separates this work from previous work is that in this work the pairwise correlations of the matched design are not necessarily equal. For both types of data, it is seen that the efficiency of the R to one design relative to the matched pairs design is influenced by the correlation among the R matching “controls” relative to the correlation between the R matching “controls” and the “case”.
Multivariate Calibration Using Covariance Adjustment
Authors: Naes Tormod
Published: May 2007

In this paper we treat linear calibration of multivariate chemical measurement instruments. Two new calibration methods for multicollinear spectral data are proposed. The methods are compared with established predictors on a set of data. The data consists of measurements of fat in fish meat and near infrared (NIR) reflectance measurements. The new methods give improvements compared with the established ones.
A Note on Optimality of Certain Rank Tests for Ordered Alternatives in Randomized Blocks
Authors: Rao K. S. Madhav , Gore A. P.
Published: May 2007

Nonparametric tests for ordered alternatives in randomised block designs based on within block rankings have been proposed by many authors. This note is concerned with the optimality of the choice of so‐called regression constants usually considered in such rank tests. Some examples are discussed.
Two — Sample Rank Tests in General Models
Authors: Brunner E. , Neumann N.
Published: May 2007

In the several sample case for independent observations suitable rank tests can be derived, if a location model is assumed. In more general models it is difficult to deduce such statistics. If only two samples are considered, rank tests can be developed without problems. For general two‐sample designs rank statistics and their associated variance estimators are derived.
Further Investigations on the Robustness of the Standardized Selection Difference
Authors: Rasch D.
Published: May 2007

The robustness of the standardized selection difference is investigated for the family of central chi‐squared‐distributions.

The results are compared with those for the uniform, a family of triangular distributions and the exponential distribution. Beside these exact results and some simulation results are considered.
Two Estimators of Mean Frequency in Products of Multinormal Probability Models
Authors: Onukogu Ike B.
Published: May 2007

Two estimators, one additive the other multiplicative, are considered for mean frequencies in a complete three‐way table. Using the mean square error criterion it is shown that preference for the additive estimator can be as high 7/8 in tables with row‐column independence and in homogeneous tables. Extension to other estimators are discussed.
Tables of Bonferroni‐limits for Simultaneous F‐Tests
Authors: Ludwig O. , Gottlieb R. , Lienert G. A.
Published: May 2007

Bonferroni adjusted F‐tables are given for α=0.10 and α = 0.001 with degrees of freedom following classical tables of Fisher and Yates. The tables may be used in simultaneous analysis of variances or in evaluating binomial tests by means of F‐tables in configural frequency testing.
Estimating Ratio of Proportions Using Auxiliary Information
Authors: Singh G. , Singh R. K. , Kaur P.
Published: May 2007

The problem of estimation of ratio of population proportions is considered and a difference‐type estimator is proposed using auxiliary information. The bias and mean squared error of the proposed estimator is found and compared to the usual estimator and also to WYNN'S (1976) type estimator. An example is included for illustration.
A Stochastic Epidemic Model with Seasonal Variations in Infection Rate
Authors: Prajneshu  , Gupta C. K. , Sharma Usha
Published: May 2007

In this paper we consider a modification of Bailey's stochastic model for the spread of an epidemic when there are seasonal variations in infection rate. The resulting nonlinear model is analyzed by employing the diffusion approximation technique. We have shown that for a large population the process, on suitable scaling and normalization, converges to a non‐stationary Ornstein‐Uhlenbeck process. Consequently the number of infectives has in the steady state a gaussian distribution.
Comparison of Resubstitution, Data Splitting, the Bootstrap, and the Jackknife as Methods for Estimating Validity Indices of New Marker Tests: A Monte Carlo Study
Authors: Abel U. , Berger J.
Published: May 2007

Estimating the diagnostic efficiency of marker tests on the basis of the training set is an intricate problem of discriminant analysis for which no analytical solution exists. The paper outline the problem, describes various popular estimation procedures and presents the results of computer simulations comparing the estimators with respect to both bias and variance.
Pre‐post Treatment Evaluation by Symmetry Testing in Square Contingency Table
Authors: Havránek T. , Lienert G. A.
Published: May 2007

Starting from an r × r contingency table derived from ordinal pre‐ and post treatment observations, the traditional Bowker symmetry test is suggested to be replaced by one of the following alternatives (1) a globals test of general improvement, (2) a set of simultaneous symmetry tests of differential improvement without assuming general improvement under H0 and (3) a set of simultaneous symmetry tests beyond assuming general improvement under H0. The tests are illustrated by a bivariate example of observing neuroticism and introversion binarily (+, ‐) before and after Rogerian psychotherapy in a sample of clients.
A Note on the Bonferroni's Inequalities
Authors: Mǎrgǎritescu E.
Published: May 2007

In this note we present improved Bonferroni type inequalities for the union of a set of nonexchangeable events. These new bounds are stronger than or equivalent with the bounds proposed by KOUNIAS (1968), HUNTER (1976), MARGOLIN & MAURER (1976), GALAMBOS (1977) and by Mǎrgǎkritescu (1983). In the particular case of the exchangeable events, the bounds given by SOBEL & UPPULURI (1972) can be derived. A generalization in terms of a partition of {1, 2, …, n} is also established.
A Note on Maximum Likelihood Ratio Test of No Outliers in Regression Models
Authors: Paul S. R.
Published: May 2007

A derivation of the maximum likelihood ratio test for testing no outliers in regression models is given using the method of WETHERILL (1981, pp. 106–107) for estimating the regression parameters. This method is essentially similar to the one outlined in BARNETT and LEWIS (1978, p. 263), although by our detailed derivation it is easier to see that the maximum likelihood estimate of θ of model (3) under the hypothesis that the ith observation in an outlier is the same as that obtained from model (1) when the ith observation is removed.
Conditional Quadratic Discrimination in the Identification of Biological Markers for Disease Screening
Authors: Rawlings R. R. , Graubard B. I. , Teper S. , Ryback R. S. , Eckardt M. J.
Published: May 2007

Conditional multivariate normal density functions are used to construct conditional quadratic discriminant functions that adjust for covariate differences between disease groups. An expected actual error rate for the conditional discriminant function is defined. The purpose of this paper is to use the conditional quadratic discriminant function and its misolassification error rate in order to help determine if a set of discriminators is a good biological marker for disease screening. The conditional quadratic discriminant analysis is illustrated using data from two alcoholism classification problems. It is shown how the discriminant functions can identify a set of variables that can be used as biological markers.
A Stochastic Model for Estimating Adolescent Sterility Among Married Women
Authors: Agrafiotis G. K.
Published: May 2007

In this paper a stochastic model is presented for the time to the first conception of a cohort of married women. By identifying three states “adolescent sterility”, “ovulation” and “conceived”, into which the women can be placed, the model incorporates individual differences for the women in the “adolescent sterility” state which allow for the individual characteristics to affect the conversion of these women into the “ovulation” state. Using straightforward probabilistic arguments it is shown that the model provides a close fit to recently published data, compares favorably with previously published models on the same subject and it is useful for planning purposes in predicting future developments.
Asymptotic Expansions and Estimation of the Expected Error Rate for Equal‐Mean Discrimination with Uniform Covariance Structure
Authors: Marco Virgil R. , Young Dean M. , Turner Danny W.
Published: May 2007

The asymptotic error rate of the equal‐mean, uniform‐covariance‐matrix classification rule is approximated by a first order asymptotic expansion. The approximation is compared for accuracy with a Monte Carlo simulation. Finally, an estimator of the error rate and an estimator of the variance of the error rate estimator are derived and applied to a classical example.
On the Asymptotic Relative Efficiency of the Mantel‐Haenszel Test
Authors: Haber M.
Published: May 2007

The Mantel‐Haenszel test is optimal when the odds ratio is constant. This paper investigates the effects of departures from the assumption of a constant odds ratio on the behavior of the Mantel‐Haenzel test. A simple approximation is proposed for the non‐null distribution of the test statistic. Based on this approximation, the asymptotic relative efficiency of the Mantel‐Haenszel test, compared to the overall χ2test for no partial association, is calculated. For the case of 2 strata, it is shown that the Mantel‐Haenszel test is efficient as long as the logarithms of the odds ratios are of the same sign and their absolute values exceed 1.
The Linear Discriminant Function: Sampling from the Truncated Normal Distribution
Authors: Kocherlakota S. , Balakrishnan N. , Kocherlakota K.
Published: May 2007

A study is made of the behaviour of the linear discriminant function in the classification of an observation when sampling from a truncated normal distribution. It is shown that the truncation proves ‘beneficial’ in that it reduces the error rates.
Note on Systematic Sampling
Authors: Bennett B. M.
Published: May 2007

In the use of systematic sampling in surveys it is known that the effect of negative correlations (=ϱwst) between deviations from stratum means of pairs of items in the same systematic sample is such that the resulting variance V(ȳst) can be zero for systematic sample means ȳst (e.g., Cochran, 1977, ch. 8). For such populations systematic sampling is then superior both to stratified sampling (one unit per stratum) and to simple random sampling.

Cochran (loc. cit.) does not identify special types of finite populations for which ϱwst = −1/(n ‐1) and hence V(ȳst) =0. It is the purpose of this paper to present one type of population for which this condition is satisfied.
Inverse Sampling in Case Control Studies Involving a Rare Exposure
Authors: Kikuchi David A.
Published: May 2007

In case‐control studies where the outcome is not uncommon but the exposure is rare, inverse sampling may be used to reduce the total number of subjects required to find a fixed number of exposed cases and controls. The sampling distribution is negative binomial rather than binomial. Logistic regression for adjustment of covariates may be implemented on the computer program GLIM by the appropriate use of macros. An example is given.
Applications of Logistic Model to Medical Research
Authors: Jain S.
Published: May 2007

The estimation of odd ratio from contingency tables is one of the main problems faced by medical researchers. The purpose of this paper is to review and present applications of logistic model and its connection to odd ratio. Numerical examples are given illustrating the use of logistic model for estimating odd ratio.
Nonparametric Identification of Multivariate Improvement Effects Using Configural Analysis of Complementary Increments (CACI) from Pre‐post Treatment Designs
Authors: Lienert G. A. , Von Eye A.
Published: May 2007

This paper introduces configural analysis of complementary increments (CACI), a method for detecting multivariate shifes in location. CACI is based on the concept of multivariate point symmetry of dichotomous increments of outcome variables from pre‐to‐post treatment. Two‐sample CACI allows the evaluation of multivariate treatment effects even if there is a confound with spontaneous remission. The example given was taken from research on drugs. Clinical application and generalizations are also discussed.
On Testing Equality of Means of Correlated Variates with Incomplete Data
Authors: Bhoj D. S.
Published: May 2007

A statistic is proposed for testing the hypothesis of equality of the means of a bivariate normal distribution with unknown common variance and correlation coefficient when observations are missing on one of the variates. Expressions for the second and fourth central moments of the statistic are obtained. These moments are used to approximate the distribution of the statistic by a Student's t distribution under the null hypothesis. The powers of the test are computed and compared with those of the conventional paired t and the other known statistics.
Nonparametric Comparison of Longitudinal Response Patterns from Unpaired Samples Using Configural Frequency Analysis
Authors: Lienert G. A. , Von Eye A.
Published: May 2007

Nonparametric methods of Configural Frequency Analysis (CFA) for the comparison of longitudinal response patterns are discussed. In particular, methods of transforming response patterns into profiles that can be analyzed using CFA are presented. When two independent samples are given, two sample CFA can be applied to perform local testing. An example is given from research on obesity. Two sample CFA of response pattern is compared to methods of global testing.
On Setting Limits on Bodily Fluids for Classifying Individuals as Pathological
Authors: Chou Youn‐Min , Owen D. B.
Published: May 2007

The problem solved in this paper is that of determining the minimum sample size for setting the ‘normal’ range for bodily fluids. The proportions of too low and too high values which are considered ‘abnormal’ are chosen based upon medical considerations. The criterion used to determine the minimum sample size is that the proportions of the too low and too high values will be not exceeded by more than a prescribed amount with a given probability. The resulting limits are β‐expectation tolerance limits with the added condition just noted, and are labeled β‐expectation inner tolerance limits.
Competing Risk Analysis of Censored Survival Data
Authors: Spivey Lonita B. , Gross Alan J.
Published: May 2007

A competing risk model is developed to accommodate both planned Type I censoring and random withdrawals. MLE's, their properties, confidence regions for parameters and mean lifetimes are obtained for a model regarding random censoring as a competing risk and compared to those obtained for the model in which withdrawals are regarded as random censoring. Estimated net and crude probabilities are calculated and compared for the two models. The model is developed for two competing risks, one following a Weibull distribution and the other a Rayleigh distribution, and random withdrawals following a Weibull distribution.
On the Use of Factor Scores for Prediction
Authors: Schönemann P. H. , Haagen K.
Published: May 2007

There are two types of indeterminacy problems in factor analysis: the indeterminacy of the parameters, which is also known as the problem of identification, and the indeterminacy of the factor scores. The second problem, which will be treated here, is of great importance to the social sciences, given that the factor analysis model was historically developed with the theory of measuring intelligence, where the main interest was to determine one person's intelligence numerically. As a consequence of the indeterminacy of factor scores we will show, by means of a numerical example, that any criterion, including the dates of easter sunday, can be perfectly predicted by the intelligence factors.
A Note on the Characterization of the Normal Distribution
Authors: Ahsanullah M.
Published: May 2007

Suppose X1, X2,…, Xn are independent and identically distributed random variables with absolutely continuous distribution function F. It is known that if F is standard normal distribution then (i)∑X2i is a chi‐square with n degrees of freedom and (ii)nX¯2 is a chi‐square with 1 degrees of freedom where X¯=1/n ∑Xi. Here the above two properties are utilized to characterize the normal distribution.
On the Assessment of the Performance of Multiple Test Procedures
Authors: Bauer P.
Published: May 2007

Based on the concept of the multiple level of significance two criteria for assessing the performance of multiple tests are proposed: The simultaneous power is defined as the probability of rejecting all false null hypotheses. The probability of a correct decision is defined as the probability of correctly rejecting all false null hypotheses and accepting all true ones. Both criteria are discussed for nonstagewise and stagewise procedures in case of independent test statistics. For the example of 5 independently and normally distributed test statistics the values of the two criteria are calcutated under reasonably simple alternatives.
On Estimating Missing Values in Linear Discriminant Analysis – Part I
Authors: Hufnagel G.
Published: May 2007

The application of discriminant analysis like other multivariate procedures is essentially complicated with incomplete data. Therefore several methods for handling missing observations occuring in initial samples were compared with each other. Recommendations are given for selecting a suitable method depending on underlying parameters.
A Characterization of the Bivariate Exponential Distribution
Authors: Nair N. U. , Nair V. K. R.
Published: May 2007

In this article a characterisation of the Gumbel's Bivariate Exponential Distribution is established on the basis of the properties of the conditional expectation of the component variables. The characterising property is proposed as the definition of lack of memory in the bivariate case.
Singlet–Singlet Annihilation Leading to a Charge‐Transfer Intermediate in Chromophore‐End‐Capped Pentaphenylenes
Authors: Fron Eduard , Schweitzer Gerd , Jacob Josemon , Van Vooren Antoine , Beljonne David , Müllen Klaus , Hofkens Johan , Van der Auweraer Mark , De Schryver Frans C.
Published: May 2007

The excited‐state properties of two peryleneimide chromophore end‐capped pentaphenylene compounds were investigated in detail using femtosecond transient absorption and single‐photon timing experiments. Singlet–singlet annihilation was found to promote one chromophore into a higher excited state and results in the formation of an ultra‐short‐living intermediate charge‐transfer (CT) state in the Sn–S1deactivation pathway. In low‐polarity solvents, this CT state is found to be energetically higher than the first excited state and thus cannot be populated via one‐photon excitation. The observed CT state decays with a time constant of about 1 ps to form the lowest singlet excited state. These results demonstrate the potential use of the singlet–singlet annihilation as a novel tool in studying reactions occurring in states that are energetically above the S1.
Defect‐tolerant nanoelectronic pattern classifiers
Authors: Lee Jung Hoon , Likharev Konstantin K.
Published: May 2007

Mixed‐signal neuromorphic networks (‘CrossNets’), based on hybrid CMOS/nanodevice circuits, may provide unprecedented performance for important pattern classification tasks. The synaptic weights necessary for such tasks may be imported from an external ‘precursor’ network with either continuous or discrete synaptic weights (in the former case, with the quantization—‘clipping’—due to the binary character of the elementary synaptic nanodevices—latching switches.) Alternatively, the weights may be adjusted ‘in situ’ (inside the CrossNet) using a pseudo‐stochastic method, or set‐up using a mixed‐mode method partly employing external circuitry. Our calculations have shown that CrossNet pattern classifiers, using any of these synaptic weight adjustment methods, may be remarkably resilient. For example, in a CrossNet with synapses in the form of two small square arrays with 4 × 4 nanodevices each, the resulting weight discreteness may have a virtually negligible effect on the classification fidelity, while the fraction of defective devices which affects the performance substantially ranges from ∼20% to as high as 90% (!), depending on the training method. Copyright © 2007 John Wiley & Sons, Ltd.
Transcription factors Mesp2 and Paraxis have critical roles in axial musculoskeletal formation
Authors: Takahashi Yu , Takagi Atsuya , Hiraoka Shuichi , Koseki Haruhiko , Kanno Jun , Rawls Alan , Saga Yumiko
Published: May 2007

Mesp2 and Paraxis are basic helix–loop–helix (bHLH) ‐type transcription factors coexpressed in the presomitic mesoderm (PSM) and are required for normal somite formation. Here, we show that Mesp2/Paraxis double‐null mice exhibit a distinct phenotype unexpected from either Mesp2 or Paraxis single‐null mice. In the posterior region of the body, most of the skeletal components of both the vertebral body and neural arches are severely reduced and only a rudimental lamina and ribs remain, indicating a strong genetic interaction in the sclerotomal cell lineage. However, yeast two‐hybrid analyses revealed no direct interaction between Mesp2 and Paraxis. The Mesp2/Paraxis double‐null embryo has caudalized somites, revealed by expanded Uncx4.1 expression pattern observed in the Mesp2‐null embryo, but the expression level of Uncx4.1 was significantly decreased in mature somites, indicative of hypoplasia of lateral sclerotome derivatives. By focusing on vertebral column formation, we found that expressions of Pax1, Nkx3.1, and Bapx1 are regulated by Paraxis and that Pax9 expression was severely affected in the Mesp2/Paraxis double‐null embryo. Furthermore, the expression of Pax3, a crucial factor for hypaxial muscle differentiation, is regulated by both Mesp2 and Paraxis in the anteriormost PSM and nascent somite region. The present data strongly suggest that patterning events by bHLH‐type transcription factors have deep impacts on regional chondrogenic and myogenic differentiation of somitic cells, mainly by means of control of Pax genes. Developmental Dynamics 236:1484–1494, 2007. © 2007 Wiley‐Liss, Inc.
Synthesis and Glycosidase Inhibitory Activities of Pyrrolidines and Piperidines with N‐(Polyhydroxyalkyl) Side Chains
Authors: Boutefnouchet Sabrina , Moldvai István , Gács‐Baitz Eszter , Bello Claudia , Vogel Pierre
Published: April 2007

Amidification of L‐proline (3) with (+)‐(R,R)‐6 and (–)‐(S,S)‐tartaric anhydride diacetate (7) gave N‐substituted L‐proline derivatives 8a,b, respectively. Acids 8a,b were transformed into diesters 9a,b with MeOH/HCl. Similar reactions with methyl (2S,4R)‐4 and (2R,4S)‐4‐acetoxypipecolate (5) led to bicyclic lactams 14a,b and 15a. Compounds 8a,b were converted into N‐(trihydroxybutyl)pyrrolidine derivatives 8c,d, 10a,b and 11a,b. Methyl (2S,4R)‐20a and (2R,4S)‐4‐acetoxy‐N‐[(2S,3S)‐1,2,3‐trihydroxybutyl]pipecolate (20b) were obtained by displacement of (–)‐(2S,2S)‐2‐O‐benzyl‐3,4‐O‐isopropylidene‐1‐deoxy‐1‐iodothreitol (19) by 4 and 5. Compounds 20a,b were converted into (2S,4R,2′S,2′S)‐21a and(2R,4S,2′S,3′S)‐4‐hydroxy‐2‐hydromethyl‐N‐(2‐benzyloxy‐3,4‐isopropylidenedioxy)piperidine (21b) and finally into unprotected pentols 22a,b. Nonprotected (2S,2′S,3′S)‐11a and (2S,2′R,3′R)‐N‐(1,2,3‐trihydroxybutyl)prolinol (11b), as well as 22a,b, did not inhibit any of the 13 glycosidases assayed. However, a triacetoxy derivative, (2S,3S)‐2,3‐diacetoxy‐4‐[(2R,4S)‐4‐acetoxy‐2‐(methoxycarbonyl)piperidin‐1‐yl]‐4‐oxobutanoic acid (13b) is an inhibitor (IC50 = 157 μM) of α‐L‐fucosidase from bovine kidney.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
On the selective local stabilization of the mixed Q1–P0 element
Authors: Qin Jinshui , Zhang Shangyou
Published: May 2007

In this paper we study the stability and performance of the quadrilateral finite element 𝒬1–𝒫0 (bili‐ near/constant) for the Stokes equations. We set up a framework to show the stability of the element for a wide range of meshes with macroelement patches. We apply the new theory to show the stability of 𝒬1–𝒫0 elements on some previously studied meshes and on some newly suggested meshes. Nevertheless such earlier and newly suggested meshes are not effective in practice, compared to the traditional unstable meshes for the 𝒬1–𝒫0 element. The new theory leads naturally to a general idea in treating instability of square 𝒬1–𝒫0 elements by the local stabilization on macroelement patches of larger, but fixed sizes. The good performance of the traditional 𝒬1–𝒫0 square elements with filtering can be kept
in some cases after the local stabilization. Some numerical tests are provided to support the theory and to show the performance of stabilized 𝒬1–𝒫0 elements. Copyright © 2007 John Wiley & Sons, Ltd.
Die Grenzen des Wachstums
Authors: Sander Martin , Hummel Jürgen , Klein Nicole , Clauss Marcus
Published: April 2007

Giganten auf der Spur: Wie der Organismus der 50 Tonnen schweren Riesensaurier funktionierte und wie sich ihre imposante Körpergröße entwickeln konnte
Des Kaisers neue Kolonien
Authors: Schmidt Wilhelm R.
Published: April 2007

Das Koloniale Bildarchiv in Frankfurt bietet einzigartige Bildzeugnisse zur deutschen Kolonialgeschichte. Die Sammlung war lange Zeit vergessen. Nach ihrer aufwändigen Erschließung und Digitalisierung stehen die Fotodokumente heute Forschern im In‐ und Ausland via Internet zur Verfügung
A new convenient way to synthesize 1‐hydroxyphosphonates from heterocyclic aldehydes and ketones under microwave irradiation
Authors: Feng Dexin , Chen Ruyu , Huang You , Song Haibin
Published: May 2007

A simple and efficient method has been developed for the synthesis of 1‐hydroxyphosphonates from heterocyclic aldehydes and ketones under solvent‐free conditions using microwave irradiation. Various phosphites have been used to find the influence of steric exclusion on the reaction. The products are readily obtained in satisfactory yields, on the solid support of MgO. The reactions are also induced by oil‐heat, and we find that the condition of microwave is better than oil‐heat with respect to reaction times and product yields. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:347–353, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20304
Sulfamic acid: An efficient and green catalyst for synthesis of 1,5‐benzodiazepines under solvent‐free conditions
Authors: Xia Min , Lu Yue‐dong
Published: May 2007

It is described that sulfamic acid can be utilized as an effective and green catalyst for the synthesis of 1,5‐benzodiazepines in high yields from the solvent‐free condensation of o‐phenylenediamine (1) and ketones (2). © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:354–358, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20305
Synthesis, structures, and biological activities of new 1H‐1,2,4‐triazole derivatives containing pyridine unit
Authors: Liu Jian‐Bing , Tao Wei‐Feng , Dai Hong , Jin Zhong , Fang Jian‐Xin
Published: May 2007

Fourteen new 1H‐1,2,4‐triazole derivatives containing pyridine moiety were synthesized by condensation of 1‐(pyridine‐3‐yl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)ethanone with aryl aldehydes, and their reaction conditions were studied. The title compounds were screened for their antibacterial and plant growth regulatory activities. The screening data revealed that most of the compounds showed some antifungal and plant growth regulatory activities. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:376–380, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20308
Synthesis and anti‐HIV activity of substituted 1,2,4‐triazolo‐thiophene derivatives
Authors: Al‐Soud Yaseen A.
Published: May 2007

A new series of substituted 1,2,4‐triazoles bearing thiophene molecules 8 and 10 has been synthesized from cycloaddition of thiophene 3‐and 2‐carbonitriles 5 and 9, respectively, with the reactive cumulene intermediates 4. The newly synthesized products have been evaluated for their anti‐HIV activity. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:443–448, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20319
Tiagabine for social anxiety disorder
Authors: Dunlop Boadie W. , Papp Laszlo , Garlow Steven J. , Weiss Paul S. , Knight Bettina T. , Ninan Philip T.
Published: May 2007

Tiagabine, a selective gamma‐aminobutyric acid (GABA) reuptake inhibitor was evaluated for the treatment of patients with social anxiety disorder (SAD). Adults with SAD received open‐label tiagabine 4–16 mg per day for 12 weeks. Intent‐to‐treat data are available for 54 patients with improvement demonstrated in Liebowitz Social Anxiety Scale, Clinician Global Impression‐Severity (CGI‐S) and ‐Improvement (CGI‐I), Social Phobia Inventory, and Sheehan Disability Scale scores. In all, 40.7% (22/54) of the intent to treat sample and 63.0% (17/27) of the completer sample were considered CGI responders (CGI‐I score of one or two). Tiagabine was generally well tolerated. Results of this pilot study suggest that tiagabine may be an option for the treatment of patients with SAD. Larger, controlled studies are required to fully elucidate the potential of tiagabine for the treatment of SAD. Copyright © 2007 John Wiley & Sons, Ltd.
Effect of ion exchange on hardness and fracture toughness of dental porcelains
Authors: Cesar Paulo Francisco , Gonzaga Carla Castiglia , Miranda Walter Gomes , Yoshimura Humberto Naoyuki
Published: April 2007

The objective of this study was to evaluate the effect of ion exchange, IE, on fracture toughness KIc and hardness H of five dental porcelains with different microstructures: B, Ceramco II/Dentstply; C, Finesse/Dentsply; Cb, Cerabien/Noritake; D, d.Sign/Ivoclar; V, Vitadur Alpha/Vita. Specimens were sintered according to manufacturers' instructions, n = 10. Vickers indentations were made on specimens' surfaces before and after IE to calculate H and KIc. IE treatment consisted in coating the surface of the specimen with slurry of KNO3 and distilled water, with subsequent drying for 20 min at 150°C and heating for 30 min at 450°C. Microstructural analysis was also performed. The measured leucite contents were 22, 15, 6, 0, and 0% for porcelains B, D, C, Cb, and V, respectively. Porcelains C, Cb, D, and V showed a significant increase in hardness after IE. Hardness of porcelain B was not affected by IE. Materials with lower leucite content tended to present higher increases in hardness after ion exchange. Ion exchange significantly increased KIc between 64 and 156% of 4 out of 5 porcelains studied. Porcelain B was the only one to present a decrease in fracture toughness after ion exchange. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
P53 mediated regulation of metallothionein transcription in breast cancer cells
Authors: Ostrakhovitch Elena A. , Olsson Per‐Erik , von Hofsten Jonas , Cherian M. George
Published: May 2007

Recent studies have shown that only breast cancer epithelial cells with intact p53 can induce metallothionein (MT) synthesis after exposure to metals. In this study, the potential role of p53 on regulation of MT was investigated. Results demonstrate that zinc and copper increased metal response elements (MREs) activity and MTF‐1 expression in p53 positive MN1 and parental MCF7 cells. However, inactivation of p53 by treatment with pifithrin‐α or the presence of inactive p53 inhibited MRE‐dependent reporter gene expression in response to metals. MTF‐1 levels remained unchanged after treatment with zinc in cells with nonfunctional p53. The introduction of wild‐type p53 in MDD2 cells, containing nonfunctional p53, enhanced the ability of zinc to increase MRE‐dependent reporter gene expression. The cellular level of p21Cip1/WAF1 was increased in MDD2 cells after p53 transfection, confirming the presence of active p53. The treatment of MN1 and parental MCF7 with trichostatin A led to a sixfold increase in the MRE activity in response to zinc. On the contrary, MRE activity remained unaltered in MDD2 cells with inactive p53. The above results demonstrate that activation of p53 is an important factor in metal regulation of MT. J. Cell. Biochem. 102: 1571–1583, 2007. © 2007 Wiley‐Liss, Inc.
New invariant of DNA sequence based on 3DD‐curves and its application on phylogeny
Authors: Zhang Xizhen , Luo Jiawei , Yang Li
Published: May 2007

The Z_inv, a new invariant based on 3DD‐curves of DNA sequence, which is simple for calculation and it approximates to the leading eigenvalues of the matrix associated with DNA sequence. The utility of our invariant is illustrated on the DNA sequence of 11 species. In this study, we use the Z_inv to analyze the phylogenetic relationships for the seven HA (H5N1) sequences of avian influenza virus. © 2007 Wiley Periodicals, Inc. J Comput Chem 2007
Calcium/calmodulin‐dependent kinase activity is required for efficient induction of osteoclast differentiation and bone resorption by receptor activator of nuclear factor kappa B ligand (RANKL)
Authors: Ang Estabelle S.M. , Zhang Ping , Steer James H. , Tan Jamie W.‐Y. , Yip Kirk , Zheng Ming H. , Joyce David A. , Xu Jiake
Published: May 2007

Calcium/calmodulin‐dependent protein kinase (CaMK) is a major down stream mediator of Ca2+ signaling in a wide range of cellular functions, including ion channel and cell cycle regulation and neurotransmitter synthesis and release. Here we have investigated the role of the CaMK signaling pathway in osteoclast differentiation and bone resorption. We observed that the CaMKI, CaMKII γ isoforms were present in both bone‐marrow derived macrophages and RAW264.7 murine macrophage cell line, and that expression persisted during osteoclast differentiation in the presence of receptor activator of nuclear factor kappa B (NF‐κB) ligand (RANKL). RANKL‐induced differentiation was accompanied by increased cyclic AMP response element transcriptional activity, and ERK phosphorylation, which are both downstream targets of CaMK. Two selective inhibitors of CaMKs, KN‐93 and KN‐62, inhibited osteoclastogenesis in a time and concentration‐dependent manner. This was accompanied by suppression of cathepsin K expression and osteoclastic bone resorption, which are markers for differentiated osteoclast function. KN‐93 and KN‐62 both inhibited RANKL‐induced ERK phosphorylation and CREB transcriptional activity. These findings imply a role for CaMK in osteoclast differentiation and bone resorption. J. Cell. Physiol. 212:787–795, 2007. © 2007 Wiley‐Liss, Inc.
Calcium oscillations induced by ATP in human umbilical cord smooth muscle cells
Authors: Meng Fei , To Wilson , Kirkman‐Brown Jackson , Kumar Prem , Gu Yuchun
Published: May 2007

Arterial smooth muscle cells exhibit vasomotion, related to oscillations in intracellular Ca2+ concentration, but the origin and function of these has not yet been fully determined. We measured intracellular Ca2+ using conventional fluorescent methods in primary cultured, human umbilical cord artery smooth muscle cells (HUCASMC). Spontaneous oscillations in Ca2+ was found in only 1% of all cells but exogenous, micromolar concentrations of ATP could induce Ca2+ oscillations in 70% of cells with the most common pattern being one of regular amplitude and frequency with a return to basal levels between each peak. The P2Y agonist, UTP, but not the P2X agonist αβ‐methylene ATP, could also induce Ca2+ oscillations. Once induced, these oscillations could not be blocked by G‐protein, PLC, VGCC or TRP channel antagonists applied individually, but could be prevented when antagonists were applied together. In the presence of EGTA, micromolar concentrations of ATP induced an elevation in intracellular Ca2+ but did not induce Ca2+ oscillations. The oscillation frequency induced by ATP was affected by bath Ca2+ concentration. Taken together, these data suggest that external Ca2+ entry maintains the Ca2+ oscillation induced by activation of P2Y receptors. Once induced, multiple mechanisms are involved to maintain the oscillation and the oscillation frequency is determined by the speed of Ca2+ refilling. Chronic hypoxia enhanced the Ca2+ response and altered the oscillation frequency. We suggest that these oscillations may play a role in the maintenance of umbilical blood flow during situations in which GPCR are activated. J. Cell. Physiol. 213: 79–87, 2007. © 2007 Wiley‐Liss, Inc.
Suppression of islet allogeneic immune response by indoleamine 2,3 dioxygenase‐expressing fibroblasts
Authors: Jalili Reza B. , Rayat Gina R. , Rajotte Ray V. , Ghahary Aziz
Published: May 2007

Success of transplantation of pancreatic islets which is a promising way for restoring efficient insulin regulation in type 1 diabetes depends on lifelong use of immunosuppressive drugs. To eliminate the use of systemic immunosuppressive drugs for islet transplantation, we examined the potential use of a local immunosuppressive factor, indoleamine 2,3‐dioxygenase (IDO). Thus, the aim of this study was to determine whether local expression of IDO in bystander syngeneic fibroblasts could prevent islet allogeneic immune response in vitro. C57BL/6 (B6) mouse fibroblasts were induced to express IDO by either IFN‐γ treatment or transduction with an adenoviral vector and were co‐cultured with B6 mouse lymphocytes and BALB/c mouse pancreatic islets in the presence or absence of an IDO inhibitor. Proliferation of lymphocytes were then assessed using [3H]‐thymidine incorporation assay. IDO‐expression by co‐cultured syngeneic fibroblasts resulted in a five‐fold decrease in lymphocyte proliferation rate upon stimulation of lymphocytes by allogeneic mouse pancreatic islets (21.9% ± 5.3 and 22.1% ± 4.9 in the preparations with IFN‐γ treated and genetically modified IDO‐expressing fibroblasts, respectively vs. 100% in control groups, P < 0.01). Allogeneic response was restored when IDO inhibitor was added to the culture indicating that suppression was due to IDO. In conclusion, this study shows that local expression of IDO by syngeneic bystander fibroblasts can suppress in vitro proliferation of lymphocytes in response to stimulation with allogeneic pancreatic islets. This local immunosuppressive function of IDO may be employed for development of a novel alternative strategy for preventing allogeneic islet graft rejection. J. Cell. Physiol. 213: 137–143, 2007. © 2007 Wiley‐Liss, Inc.
Changes in chromosome positioning may contribute to the development of diseases related to X‐chromosome aneuploidy
Authors: Petrova Natalia V , Yakutenko Irina I. , Alexeevski Andrei V. , Verbovoy Valentin A. , Razin Sergey V. , Iarovaia Olga V.
Published: May 2007

The radial positions of the centromeric regions of chromosomes 1 and X were determined in normal male fibroblasts (XY) and in fibroblasts from a patient with a rare case of XXXXY polysomy. The centromeric regions and presumably the whole territories of active X chromosomes were demonstrated to occupy similar, although not identical, positions in XY and XXXXY cells. The centromeres of inactive X chromosomes (Barr bodies) were located closer to the nuclear periphery as compared with the centromeres of active X chromosomes. In addition, it was established that the nuclear radial position of gene‐rich chromosome 1 was changed in XXXXY cells as compared to normal XY cells. The data are discussed in the context of the hypothesis postulating that changes in nuclear positioning of chromosomal territories induced by the presence of extra copies of individual chromosomes may contribute to the development of diseases related to different polysomies. J. Cell. Physiol. 213: 278–283, 2007. © 2007 Wiley‐Liss, Inc.
Solid pseudopapillary neoplasms of the pancreas: An updated experience
Authors: Goh Brian K.P. , Tan Yu‐Meng , Cheow Peng‐Chung , Alexander Chung Yaw‐Fui , Chow Pierce K.H. , Wong Wai‐Keong , Ooi London L.P.J.
Published: May 2007

Introduction

The aim of this study is to report an update of the surgical experience at a single institution with these unusual tumors.

Methods

Sixteen consecutive patients who underwent surgery for a pathologically confirmed solid pseudopapillary neoplasm (SPPN) were retrospectively reviewed.

Results

Fifteen of the patients were female and the median age at diagnosis was 30 years (range, 14–53 years). Abdominal and back pain were the most common presenting symptoms. The tumors appeared on cross‐sectional imaging as solid and cystic (n = 14) or cystic (n = 2) masses. The median tumor size was 9.5 cm (range, 5.0–24.0 cm). All 16 patients had curative resections including 3 pancreaticoduodenectomies and 13 distal pancreatectomies. Three patients required extended resections including pancreaticoduodenectomy with portal vein resection, distal pancreatectomy with tranverse colectomy, and distal pancreactomy with omentectomy. Two of the resections were R1 whereas 14 were R0. All patients were alive and disease‐free at a median follow‐up of 43 months (range, 3–186 months).

Conclusion

SPPNs should be considered in young women presenting with a large solid‐cystic pancreatic mass. Aggressive en bloc resection should always be attempted including resection of concomitant metastases as patients demonstrate excellent long‐term survival even in the presence of distant spread. J. Surg. Oncol. 2007;95:640–644. © 2007 Wiley‐Liss, Inc.
The Fractal Character of Localizable Measure‐Valued Processes, II. Localizable Processes and Backward Trees
Authors: Zähle U.
Published: May 2007

Regard a large population of infinitesimal particles (i.e. a measure) in the case, when the particles evolve (i.e. move, branch, die) independently of each other. Those evolutions we will call localizable. In the present part of this paper we answer at first the question about the structure of localizable evolutions, which take place in one step (independent clustering of measures). In localizable evolutions one can follow the path of any particle (and their predecessors) surviving up to some fixed time. The totality of these paths is the backward tere corresponding to this time point. In the case of continuous time localizable Markov evolutions the random backward tree measure is constructed via finite‐dimensional distributions using the extension theorem from part I.
On the McKean‐Vlasov Limit for Interacting Diffusions
Authors: Gärtner Jürgen
Published: May 2007

For a system of diffusions in a domain of Rd with long‐range weak interaction the behavior of the associated empirical process is studied. Under mild growth and smoothness assumptions on the drift and diffusion coefficients such as coercivity and monotonicity conditions the law of large numbers and the propagation of chaos are proved. Existence and uniqueness of the weak solution to the McKean ‐ Vlasov equation and the associated non‐linear martingale problem are investigated.
On Continuity and Decomposition of Positive Definite Functions
Authors: Sasvári Zoltán
Published: May 2007

Let G be a locally compact commutative group and let g and h be positive definite functions on G, which are not identically zero. We show that continuity of gh̄ implies the existence of a character γ of Gd (the discrete version of G) such that γg and γh are continuous. As corollary we get a special case of a result of K. de Leeuw and I. Glicksberg concerning almost continuous group representations. In the second part of the paper we prove decomposition theorems for positive definite functions defined on a neighbourhood of the zero.
Oscillation Theorems for Second Order Nonlinear Differential Equations with Damping
Authors: Grace S. R.
Published: May 2007

In this paper, we present some new criteria for the oscillation of the differential equation with damping where p(t) and q(t) are allowed to change signs on [t0 ∞]. These criteria are obtained by using an integral averaging technique and can be applied in some special cases in which other classical oscillation results are not applicable.
On the Vector‐Valued Hilbert Transform
Authors: Defant Martin
Published: May 2007

Let H : Lp (R) → Lp(R), 1 < p < ∞ be the real HILBERT transform. A bounded, linear operator u:E → F (E, F BANACH spaces) is a HT‐operator, if the mapping u ⊗ H : E ⊗ L2(R, E) → L2(R, F) has a bounded, linear extension to L2(R) → L2(R, F). For E = F and u = idE BOURGAIN [3] and BURKHOLDER [5] have shown that this holds if and only if E ϵ UMD. We study these HT‐operators and, in particular, we construct a HT‐operator which is not UMD‐factorable. Furthermore, we show that a UMD‐space E is a HILBERT space if and only if |idE ⊗ H| = 1.