bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Method of Regression of Time‐series Based on a Mathematical Connection Between Path and Compartmental Analyses
Authors: Eöry A. 
Published: May 2007

AbstractIn the regression analysis of time‐series the error terms may be serially correlated with the results. In this case the possibility arises that the expectations and adjustment processes are themselves mis‐specifications of the correct behavioural relationships. In this paper an analogy is pointed out between the compartmental‐analysis and the path analysis by the author. It will be argued that the time‐series of the standardized partial regression coefficients (path coefficients or beta weights) computed from the cross‐sectional data, have to be analysed instead of applying ordinary least squares directly to the timeseries. An application of the new method is briefly discussed.
Use of known Coefficients of Variation in the Estimation of the Common mean of two Normal Populations
Authors: Dabli P. V. 
Published: May 2007

AbstractThe problem of estimating the common mean of two normal populations N(ϕ, a1ϕ2) and N(ϕ, a2ϕ2) where the coefficients of variation of two populations respectively, are known constants, on the basis of two independent random samples, one from each population, is considered. The minimum mean square estimator is proposed. It is also shown that the proposed estimator is Best Asymptotic Normal (BAN) estimator. It is pointed out that the result can be generalized to k population problem. It is remarked that the same method works, also for the problem of estimating the common standard deviation of k normal populations when coefficients of variation are known.
Methods for Analyzing Odds Ratios in a 2× C Contingency Table
Authors: Hosmer David W. , Hartz Stuut C. 
Published: May 2007

AbstractThis paper presents produrea for the analysis of the odds ratio and log odds ratio for a 2×C contingency table. The proposed procedurea provide a more unified approach to study of the trend of the odds ratio as a measure of association between a risk indioator and an “outcome” variable than traditional form of analyeis. The methodology is illustrated with an example from the epidemiologic literature.
Simulation Models for the Dynamic Analysis of Molecular‐Genetic Control Systems. Part 2: Application of the discrete stochastic model to the system analysis of some elementary epigenetic control systems
Authors: Böttner R. , Bellmann K. 
Published: May 2007

AbstractThe discrete stochastic model of the gene‐expression regulation — elaborated in the first part of this work — is used for the dynamic analysis of some simple molecular‐genetic control systems. The aim is the determination of stationary states and of their stability behaviour, the finding and understanding of the functional properties of the dynamics of epigenetic systems and the study of the integral behaviour (reliability) in case of stochastically disturbed single processes.Connections between simple processes of the gene‐expression and partial sections of the secondary differentiation are investigated and an approach for the formal description of the overlapping and time coordination of simple differentiation programs are described.For the mutant Lambda sus O29, which is unable to replicate, the regulation of the early development is investigated and a good congruence between experimental and theoretical results is obtained. Predictions on a hypothetic mutant and suggestions for experiments are made.
Determination of Number and Size of Spherical Particles from Extraction Replicas
Authors: Likes J. 
Published: May 2007

AbstractFor spherical particles randomly dispersed in the space of a specimen the estimators of the parameters of the space structure from the measurements obtained from extraction replicas are given. First an arbitrary form of the probability density function f(x) of the diameter X and then the generalized RAYLEIGH and lognormal distributions of X are considered. Unbiased estimators of the space parameters and of parameters of these distributions are found. The variances of these estimators are given and unbiased estimators of these variances are determined.
MANOVA multiple comparisons using the generalized step‐down procedure
Authors: Subbaiah Perla , Mudholkar Govind S. 
Published: May 2007

AbstractIf the variables in MANOVA problem can be arranged according to the order of their importance, then J. ROY'S (1958) step‐down procedure may be more appropriate than the conventional invariant inference techniques. However, it may often be possible only to identify subsets such that variables within subsets are equally important and subsets are of unequal importance. In experimental situations, it is common to have a set of variables of primary interest and another of “addon” variables. The step‐down reasoning is extended to such cases and a set of simultaneous confidence bounds based upon the procedure which uses the largest root criterion at each stage are derived. The confidence bounds are on all linear functions of means only that do not involve nuisance parameters, and are therefore suitable for studying the configuration of means. This method yields shorter intervals for contrasts among the means of the variables of primary interest compared with the conventional intervals based upon the largest root. The method is illustrated using BARNARD'S data (1935) on skull characters.
A Semi‐Markovian Model for Cell Survival after Irradiation
Authors: Jaiswal N. K. , Karmeshu  , Rangaswamy N. S. 
Published: May 2007

AbstractTo study the behaviour of a living cell exposed to radiations we investigate a stochastic model, employing for its analysis the theory of semi‐Markov and Markov renewal processes. Four states of the cell namely, normal state, damaged state 1, damaged state 2 and altered state are defined and various characteristics of interest pertaining to the cell behaviour are studied.
Estimation of Parameters in Mixtures of Distributions Arising in Cultivation Problems
Authors: Läuter H. 
Published: May 2007

AbstractIn many processes one has to describe events in which given particles or elements divide themselves so that these elements are to observe only after the division.In biological problems one meets such a situation i.e. in the cultivation of bacteria. In this paper we investigate a mathematical model which describes such a phenomenon. We give estimators for the expectation μ and the variance σ2 of the distribution of the undivided particles. Therefore we give a best linear unbiased estimator for μ and an estimator μ where a clustering of the observation is essentially.In an example for the judgment of a cultivation method we demonstrate the given estimation procedures.
Linear Logistic Latent Class Analysis
Authors: Formann Anton K. 
Published: May 2007

AbstractIn the present paper the linear logistic extension of latent class analysis is described. Thereby it is assumed that the item latent probabilities as well as the class sizes can be attributed to some explanatory variables. The basic equations of the model state the decomposition of the log‐odds of the item latent probabilities and of the class sizes into weighted sums of basic parameters representing the effects of the predictor variables. Further, the maximum likelihood equations for these effect parameters and statistical tests for goodness‐of‐fit are given. Finally, an example illustrates the practical application of the model and the interpretation of the model parameters.
Comparative Studies on the Estimation of Genetic Variances by Several Variance Components Estimation Method
Authors: Tan W. Y. , Shiue W. W. 
Published: May 2007

AbstractUsing a quantitative genetic model, this paper compares four different methods for estimating genetic variance components. Given various genetic parameters, data were generated and estimates computed. The number of negative estimates, the sample mean, the sample variance, and the sample mean squared error were computed for each method. It is shown that, if the genetic values are not very small, the traditional MATHER‐JINKS method is at least as good as any other method. The ML method might be preferable only if the genetic values are very small and the number of loci large.
Multinomial Distribution and Ascertainment by Sex
Authors: Gupta A. K. , Lindle S. G. 
Published: May 2007

AbstractNew ascertainment models taking into account partitioning by sex and without any constraint concerning dominance of alleles are proposed. These originate beginning from two major pathways. The first pathway assumes independence and that the family sizes for both males and females are known. The second pathway assumes dependence and that only the total family size is known. Ascertainment probabilities based on several different types of dependence are found. Results are obtained for incomplete multiple ascertainment.
Quantitative liquid chromatography/time‐of‐flight mass spectrometry
Authors: Williamson Leah N. , Bartlett Michael G. 
Published: May 2007

AbstractOver the last decade, time‐of‐flight (TOF) instruments have increasingly been used as quantitation tools. In addition, because of their high resolving power, they can be used for verification of empirical formulas. Historically, TOF instruments have had limited quantitation capabilities because of their narrow dynamic range. However, recent advances have improved these limitations. This review covers the rationale for using TOF for LC detection, and describes the many methods currently in the literature for the quantitation of pharmaceuticals, environmental pollutants, explosives and many phytochemicals. Copyright © 2007 John Wiley & Sons, Ltd.
Gossip‐based search selection in hybrid peer‐to‐peer networks
Authors: Zaharia M. , Keshav S. 
Published: May 2007

AbstractWe present GAB, a search algorithm for hybrid peer‐to‐peer networks, that is, networks that search using both flooding and a distributed hash table (DHT). GAB uses a gossip‐style algorithm to collect global statistics about document popularity to allow each peer to make intelligent decisions about which search style to use for a given query. Moreover, GAB automatically adapts to changes in the operating environment. Synthetic and trace‐driven simulations show that compared to a simple hybrid approach that always floods first, trying a DHT if too few results are found, GAB reduces the response time by 25–50% and the average query bandwidth cost by 45%, with no loss in recall. GAB scales well, with only a 7% degradation in performance despite a tripling in system size. Copyright © 2007 John Wiley & Sons, Ltd.
Robust incentives via multi‐level Tit‐for‐Tat
Authors: Lian Qiao , Peng Yu , Yang Mao , Zhang Zheng , Dai Yafei , Li Xiaoming 
Published: May 2007

AbstractMuch work has been done to address the need for incentive models in real deployed peer‐to‐peer networks. In this paper, we discuss problems found with the incentive model in a large, deployed peer‐to‐peer network, Maze. We evaluate several alternatives, and propose an incentive system that generates preferences for well‐behaved nodes while correctly punishing colluders. We discuss our proposal as a hybrid between Tit‐for‐Tat and EigenTrust, and show its effectiveness through simulation of real traces of the Maze system. Copyright © 2007 John Wiley & Sons, Ltd.
Development of nitric oxide synthase‐defined neurons in the sea urchin larval ciliary band and evidence for a chemosensory function during metamorphosis
Authors: Bishop Cory D. , Brandhorst Bruce P. 
Published: May 2007

AbstractWe previously reported that initiation of metamorphosis of larvae of Lytechinus pictus is negatively regulated by nitric oxide (NO) and cGMP. We have examined the expression of nitric oxide synthase (NOS) and cGMP in cells of the developing larva. A section of the post‐oral ciliary band of feeding larvae includes neural cells defined by their expression of both NOS and the echinoderm neural‐specific antibody 1E11. These neurons project processes to the pre‐oral neuropile during larval development. Larvae regenerated this section of the ciliary band after its excision, complete with NOS‐defined neurons that projected again to the pre‐oral neuropile. Excision of ectoderm containing the post‐oral ciliary band prevented a behavioral and morphogenetic response of competent larvae to biofilm, and delayed initiation of metamorphosis. Elevated cGMP levels were detected in several larval and juvenile cell types prior to metamorphosis. Treatment of larvae with ODQ, an inhibitor of soluble guanylate cyclase, decreased cGMP levels and induced metamorphosis while a generator of NO counteracted this effect, indicating inhibition of metamorphosis by NO operates via interaction with soluble guanylate cyclase. We discuss these observations, proposing that the NOS‐defined neurons in the post‐oral ciliary band have a chemosensory function during settlement and metamorphosis that involves morphologically specialized ectoderm and manipulation of fluid flow. We provide a tentative cellular model of how environmental signals may be transduced into a metamorphic response. Developmental Dynamics 236:1535–1546, 2007. © 2007 Wiley‐Liss, Inc.
Runx2 is essential for larval hyobranchial cartilage formation in Xenopus laevis
Authors: Kerney Ryan , Gross Joshua B. , Hanken James 
Published: May 2007

AbstractThe vertebrate transcription factor protein Runx2 is regarded as a “master regulator” of bone formation due to the dramatic loss of the osseous skeleton in the mouse homozygous knockout. However, Runx2 mRNA also is expressed in the pre‐hypertrophic cartilaginous skeleton of the mouse and chicken, where its developmental function is largely unknown. Several tiers of Runx2 regulation exist in the mouse, any of which may account for its seeming biological inactivity during early stages of skeletogenesis. Unlike mouse and chicken, zebrafish require Runx2 function in early cartilage differentiation. The present study reveals that the earlier functional role of Runx2 in cartilage differentiation is shared between zebrafish and Xenopus. A combination of morpholino oligonucleotide injections and neural crest transplants indicate that Runx2 is involved in differentiation of the cartilaginous hyobranchial skeleton in the frog, Xenopus laevis. Additionally, in situ hybridizations show runx2 mRNA expression in mesenchymal precursors of the cartilaginous skull, which reveals the earliest pre‐patterning of these cartilages described to date. The early distribution of runx2 resolves the homology of the larval suprarostral plate, which is one of the oldest controversies of anuran skull development. Together these data reveal a shift in Runx2 function protein during vertebrate evolution towards its exclusive roles in cartilage hypertrophy and bone differentiation within the amniote lineage. Developmental Dynamics 236:1650–1662, 2007. © 2007 Wiley‐Liss, Inc.
Stable high‐order finite‐difference methods based on non‐uniform grid point distributions
Authors: Hermanns Miguel , Hernández Juan Antonio 
Published: May 2007

AbstractIt is well known that high‐order finite‐difference methods may become unstable due to the presence of boundaries and the imposition of boundary conditions. For uniform grids, Gustafsson, Kreiss, and Sundström theory and the summation‐by‐parts method provide sufficient conditions for stability. For non‐uniform grids, clustering of nodes close to the boundaries improves the stability of the resulting finite‐difference operator. Several heuristic explanations exist for the goodness of the clustering, and attempts have been made to link it to the Runge phenomenon present in polynomial interpolations of high degree.By following the philosophy behind the Chebyshev polynomials, a non‐uniform grid for piecewise polynomial interpolations of degree q⩽N is introduced in this paper, where N + 1 is the total number of grid nodes. It is shown that when q=N, this polynomial interpolation coincides with the Chebyshev
interpolation, and the resulting finite‐difference schemes are equivalent to Chebyshev collocation methods. Finally, test cases are run showing how stability and correct transient behaviours are achieved for any degree q<N through the use of the proposed non‐uniform grids. Discussions are complemented by spectra and pseudospectra of the finite‐difference operators. Copyright © 2007 John Wiley & Sons, Ltd.
P2X7receptor stimulation upregulates Egr‐1 biosynthesis involving a cytosolic Ca2+rise, transactivation of the EGF receptor and phosphorylation of ERK and Elk‐1
Authors: Stefano Luisa , Rössler Oliver G. , Griesemer Désirée , Hoth Markus , Thiel Gerald 
Published: May 2007

AbstractThe P2X7receptor is an ATP‐gated ionotropic receptor that is permeable for small cations including Ca2+ions. Using 293 cells expressing P2X7receptors, we show that the P2X7receptor‐specific ligand 2′,3′‐O‐(4‐benzoyl‐benzoyl)‐ATP (BzATP) induces a signaling cascade leading to the biosynthesis of biologically active Egr‐1, a zinc finger transcription factor. BzATP‐triggered Egr‐1 biosynthesis was attenuated by the mitogen‐activated protein kinase kinase inhibitor PD98059, by BAPTA‐AM, the acetoxymethylester of the cytosolic Ca2+chelator BAPTA, and by an epidermal growth factor (EGF) receptor‐specific tyrosine kinase inhibitor (AG1478). These results indicate that phosphorylation and activation of extracellular signal‐regulated protein kinase ERK, elevated levels of intracellular Ca2+and the transactivation of the EGF receptor are essential for BzATP‐induced upregulation of Egr‐1. The requirement of Ca2+within the signaling cascade was upstream of Raf kinase activation. Lentiviral‐mediated expression of MAP kinase phosphatase‐1 (MKP‐1), a dual‐specific phosphatase that dephosphorylates and inactivates ERK in the nucleus, inhibited Egr‐1 biosynthesis following BzATP stimulation, indicating that MKP‐1 functions as a nuclear shut‐off device. Furthermore, the ternary complex factor Elk‐1 was phosphorylated and the transcriptional activation potential of Elk‐1 was enhanced following P2X7receptor stimulation. Expression of a dominant‐negative mutant of Elk‐1 impaired BzATP‐induced upregulation of Egr‐1 biosynthesis. Thus, Elk‐1 connects the intracellular signaling cascade elicited by activation of P2X7receptors with the transcription of the Egr‐1 gene. J. Cell. Physiol. 213: 36–44, 2007. © 2007 Wiley‐Liss, Inc.
Delivery and long‐term expression of a 135 kb LDLR genomic DNA locus in vivo by hydrodynamic tail vein injection
Authors: Hibbitt Olivia C. , Harbottle Richard P. , Waddington Simon N. , Bursill Christine A. , Coutelle Charles , Channon Keith M. , Wade‐Martins Richard 
Published: May 2007

AbstractBackgroundThe delivery of a complete genomic DNA locus in vivo may prove advantageous for complementation gene therapy, especially when physiological regulation of gene expression is desirable. Hydrodynamic tail vein injection has been shown to be a highly efficient means of non‐viral delivery of plasmid DNA to the liver. Here, we apply hydrodynamic tail vein injection to deliver and express large genomic DNA inserts > 100 kb in vivo.MethodsFirstly, a size series (12–172 kb) of bacterial artificial chromosome (BAC) plasmids, carrying human genomic DNA inserts, episomal retention elements, and the enhanced green fluorescent protein (EGFP) reporter gene, was delivered to mice by hydrodynamic tail vein injection. Secondly, an episomal BAC vector carrying the whole genomic DNA locus of the human low‐density lipoprotein receptor (LDLR) gene, and an expression cassette for the LacZ reporter gene, was delivered by the same method.ResultsWe show that the efficiency of delivery is independent of vector size, when an equal number of plasmid molecules are used. We also show, by LacZ reporter gene analysis, that BAC delivery within the liver is widespread. Finally, BAC‐end PCR, RT‐PCR and immunohistochemistry demonstrate plasmid retention and long‐term expression (4 months) of human LDLR in transfected hepatocytes.ConclusionThis is the first demonstration of somatic delivery and long‐term expression of a genomic DNA transgene > 100 kb in vivo and shows that hydrodynamic tail vein injection can be used to deliver and express large genomic DNA transgenes in the liver. Copyright © 2007 John Wiley & Sons, Ltd.
High contrast scanning nano‐Raman spectroscopy of silicon
Authors: Lee N. , Hartschuh R. D. , Mehtani D. , Kisliuk A. , Maguire J. F. , Green M. , Foster M. D. , Sokolov A. P. 
Published: April 2007

AbstractWe have demonstrated that scanning nano‐Raman spectroscopy (SNRS), generally known as tip‐enhanced Raman spectroscopy (TERS), with side illumination optics can be effectively used for analysis of silicon‐based structures at the nanoscale. Even though the side illumination optics has disadvantages such as difficulties in optical alignment and shadowing by the tip, it has the critical advantage that it may be used for the analysis of nontransparent samples. A key criterion for making SNRS effective for imaging Si samples is the optimization of the contrast between near‐field and far‐field (background) Raman signals. This has been achieved by optimizing the beam polarization, resulting in an order of magnitude improvement in the contrast. We estimate the lateral resolution of our Raman images to be ∼20 nm. Copyright © 2007 John Wiley & Sons, Ltd.
Vibrational properties of thymine, uracil and their isotopomers
Authors: Yarasi Soujanya , Billinghurst Brant E. , Loppnow Glen R. 
Published: April 2007

AbstractDensity functional theory (DFT) calculations using the B3LYP/6‐311G(d,p) basis set of ten isotopomers of thymine and four isotopomers of uracil, including the natural abundance isotopomers, are reported. Comparison of the calculated wavenumber shifts upon hydrogen, carbon and nitrogen isotopic substitution with those from experimental Raman and infrared measurements show good agreement in both the direction and the magnitude of the shift. These results are contrasted to previously reported calculations and discussed in the context of assigning the normal modes of thymine and uracil. Copyright © 2007 John Wiley & Sons, Ltd.