bluuebunny/crossref_metadata_2025 huggingface dataset:
Parkinsonism and Parkinson's disease in the elderly: A community‐based survey in Brazil (the Bambuí study)
Authors: Barbosa Maira Tonidandel , Caramelli Paulo , Maia Débora Palma , Cunningham Mauro César Quintão , Guerra Henrique Leonardo , Lima‐Costa Maria Fernanda , Cardoso Francisco
Published: February 2006

Several community‐based surveys on the prevalence of Parkinsonism and Parkinson's disease have been conducted worldwide, with variations on their methodology and results. The objective of this study is to assess the prevalence of Parkinsonism and its causes in a cohort of individuals age 64 years or older in Bambuí, a Brazilian town. In phase I, 1,186 people older than 64 years responded to a 9‐question screening questionnaire for Parkinsonism. In phase II, all subjects who scored ≥ 2 points on the test were examined independently by at least 2 movement disorder‐trained physicians. A movement disorder senior specialist excluded or confirmed the diagnosis in all suspected cases. The response rate was high for both phases (96% for phase I and 94% for phase II). The prevalence rate per 100 population over 64 years of age in this group was 7.2% for Parkinsonism of all types (n = 86). The most frequent causes were idiopathic Parkinson's disease and drug‐induced Parkinsonism, with prevalence rates of 3.3% (n = 39) and 2.7% (n = 32), respectively. The prevalence of vascular Parkinsonism was 1.1% (n = 13). We found 1 case of posttraumatic Parkinsonism and another with multiple system atrophy. In this first population‐based study of Parkinsonism conducted in Brazil, the prevalence in a cohort of elderly subjects was higher than the observed in other populations worldwide, especially because of the high rates of drug‐induced and vascular Parkinsonism. The prevalence of Parkinson's disease was similar to that observed in elderly people in door‐to‐door surveys in other American, European, and Eastern countries. © 2006 Movement Disorder Society
Local C1 solutions to some non‐linear PDE system
Authors: Callegari Emanuele , Ghisi Marina
Published: February 2006

We prove that the quasilinear initial value problem
equation image
has a unique, local in time, C1 solution, if the matrices Ai are diagonalizable and commute with each other. Copyright © 2006 John Wiley & Sons, Ltd.
Deterministic and statistical methods for reconstructing multidimensional NMR spectra
Authors: Yoon Ji Won , Godsill Simon , Kupče Eriks , Freeman Ray
Published: February 2006

Reconstruction of an image from a set of projections is a well‐established science, successfully exploited in X‐ray tomography and magnetic resonance imaging. This principle has been adapted to generate multidimensional NMR spectra, with the key difference that, instead of continuous density functions, high‐resolution NMR spectra comprise discrete features, relatively sparsely distributed in space. For this reason, a reliable reconstruction can be made from a small number of projections. This speeds the measurements by orders of magnitude compared to the traditional methodology, which explores all evolution space on a Cartesian grid, one step at a time. Speed is of crucial importance for structural investigations of biomolecules such as proteins and for the investigation of time‐dependent phenomena. Whereas the recording of a suitable set of projections is a straightforward process, the reconstruction stage can be more problematic. Several practical reconstruction schemes are explored. The deterministic methods—additive back‐projection and the lowest‐value algorithm—derive the multidimensional spectrum directly from the experimental projections. The statistical search methods include iterative least‐squares fitting, maximum entropy, and model‐fitting schemes based on Bayesian analysis, particularly the reversible‐jump Markov chain Monte Carlo procedure. These competing reconstruction schemes are tested on a set of six projections derived from the three‐dimensional 700‐MHz HNCO spectrum of a 187‐residue protein (HasA) and compared in terms of reliability, absence of artifacts, sensitivity to noise, and speed of computation. Copyright © 2006 John Wiley & Sons, Ltd.
A multigrid method for anisotropic PDEs in elastic image registration
Authors: Hömke Lars
Published: February 2006

This paper deals with the solution of a non‐linear ill‐conditioned inverse problem arising in digital image registration. In the first part of the paper, we define the problem as the minimization of a regularized non‐linear least‐squares functional, which measures the image difference and smoothness of the transformation. We study inexact Newton methods for solving this problem, i.e. we linearize the functional around a current approximation and replace the Hessian by a suitable operator in order to obtain well‐posed subproblems in each step of the iteration.

These anisotropic subproblems are solved using a multigrid solver. Due to the anisotropy in the coefficients of the underlying equations, standard multigrid solvers suffer from poor convergence rates. We discuss modifications to the multigrid components, specifically to the smoothing procedure, the interpolation and the coarse grid correction. Numerical results that demonstrate the improvements obtained with these new components are given. Copyright © 2006 John Wiley & Sons, Ltd.
Effects of sildenafil on pulmonary hypertension and exercise tolerance in severe cystic fibrosis‐related lung disease
Authors: Montgomery Gregory S. , Sagel Scott D. , Taylor Amy L. , Abman Steven H.
Published: February 2006

Cystic fibrosis (CF) patients with advanced lung disease are at risk for developing pulmonary vascular disease and pulmonary hypertension, characterized by progressive exercise intolerance beyond the exercise‐limiting effects of airways disease in CF. We report on a patient with severe CF lung disease who experienced clinically significant improvements in exercise tolerance and pulmonary hypertension without changing lung function during sildenafil therapy. Pediatr Pulmonol. © 2006 Wiley‐Liss, Inc.
IGF‐I secretion by prostate carcinoma cells does not alter tumor‐bone cell interactions in vitro or in vivo
Authors: Rubin Janet , Fan Xian , Rahnert Jill , Sen Buer , Hsieh Chia‐ling , Murphy Tamara C. , Nanes Mark S. , Horton Lindsay G. , Beamer Wesley G. , Rosen Clifford J.
Published: February 2006

BACKGROUND

IGF‐I is an important growth and differentiative factor for osteoblasts and may have a role in defining prostate cancer risk and skeletal metastases.

METHODS

Conditioned media (CM) from human prostate cancer (PC), C4‐2 and C4‐2B, which produce osteoblastic lesions, and PC‐3, which causes osteolysis, was added to MC3T3‐E1 bone cultures. SCID mice were injected intratibially with these engineered cells. Tumor bearing tibiae were analyzed by microCT and pQCT.

RESULTS

CM from PC cells increased osteoblast proliferation and differentiation and was unaltered by the type of PC cell, IGF‐I antibodies, or exogenous IGF‐I and IGFBP2. Study of intratibial PC tumors in SCID mice showed that C4‐2 cells grew slowly preserving bone structure, while PC‐3 tumors caused rapid osteolysis. Overexpression of IGF‐I did not change either tumor progression or skeletal response.

CONCLUSIONS

IGF‐I is neither necessary nor sufficient for the osteoblastic response to PC metastases. Prostate © 2006 Wiley‐Liss, Inc.
Expression of BAG‐1 protein correlates with aggressive behavior of prostate cancers
Authors: Krajewska Maryla , Turner Bruce C. , Shabaik Ahmed , Krajewski Stan , Reed John C.
Published: February 2006

Background

Differences in tumor behavior, ranging from indolent to aggressive, create a need for novel prognostic biomarkers. BAG‐1 is a co‐chaperone that regulates the activity of Hsp70, Bcl‐2, Raf‐1, growth factor, and steroid receptors (e.g., the Androgen Receptor).

Methods

Using immunohistochemical method, we explored BAG‐1 expression in prostate cancers and its association with clinicopathological parameters.

Results

BAG‐1 immunostaining was elevated in prostate cancer compared to normal prostatic epithelium. Higher nuclear BAG‐1 in hormone‐refractory (n = 34) compared to localized untreated tumors (n = 58) (P < 0.0001) suggested that upregulation of the nuclear isoform may contribute to disease progression. In 64 early‐stage patients (T2N0M0) treated with external‐beam irradiation, cytosolic BAG‐1 correlated with higher pretreatment levels of serum Prostate specific antigen (P = 0.04) and shorter time to disease progression (P = 0.00004).

Conclusions

Increased cytosolic and nuclear BAG‐1 expression may denote more aggressive variants of prostate cancer. Prostate © 2006 Wiley‐Liss, Inc.
Vaccination of hormone‐refractory prostate cancer patients with peptide cocktail‐loaded dendritic cells: Results of a phase I clinical trial
Authors: Fuessel Susanne , Meye Axel , Schmitz Marc , Zastrow Stefan , Linné Clemens , Richter Katja , Löbel Barbel , Hakenberg Oliver W. , Hoelig Kristina , Rieber E. Peter , Wirth Manfred P.
Published: February 2006

Background

Immunotherapies might represent promising alternatives for the treatment of patients with hormone‐refractory prostate cancer (HRPC). In a Phase I clinical trial, we evaluated a vaccination with dendritic cells (DCs) loaded with a cocktail consisting of HLA‐A*0201‐restricted peptides derived from five different prostate cancer‐associated antigens [prostate‐specific antigen (PSA), prostate‐specific membrane antigen (PSMA), survivin, prostein, transient receptor potential p8 (trp‐p8)].

METHODS

Eight HRPC patients received a total of four vaccinations every other week. Clinical and immunological responses were monitored by the determination of the serum PSA levels and by enzyme linked immunospot (ELISPOT) analyses, respectively.

RESULTS

Apart from local skin reactions no side effects were noted. One patient displayed a partial response (PR; PSA decrease >50%) and three other patients showed stable PSA values or decelerated PSA increases. In ELISPOT analyses, three of four PSA responders also showed antigen‐specific CD8+ T‐cell activation against prostein, survivin, and PSMA.

CONCLUSIONS

The described protocol represents a safe and feasible concept for the induction of clinical and immunological responses. The application of a peptide cocktail‐derived from different antigens as a novel treatment modality is supposed to allow for the genetic and biologic heterogeneity of PCa. Prostate © 2006 Wiley‐Liss, Inc.
Renin‐angiotensin system is an important factor in hormone refractory prostate cancer
Authors: Uemura Hiroji , Hasumi Hisashi , Ishiguro Hitoshi , Teranishi Jun‐ichi , Miyoshi Yasuhide , Kubota Yoshinobu
Published: February 2006

Background

The aim of this study was to perform a comprehensive evaluation of the renin‐angiotensin system (RAS) in prostate cancer.

Methods

We investigated the expression of RAS components in prostate cancer cells treated with hormonal agents. Real‐time PCR data showed the expression of the AT1 receptor, angiotensin I converting enzyme (ACE), and angiotensin I/II (Ang‐I/II) precursor in all 87 prostate tissue samples.

Results

Expression of these genes in hormone refractory prostate cancer (HRPC) was significantly higher than that in normal prostate tissue and untreated prostate cancer tissue. Western blot showed that protein expression of the AT1 receptor and Ang‐I/II was enhanced in LNCaP cells cultivated in steroid‐free medium. When LNCaP cells were stimulated with dihydrotestosterone (DHT), estradiol (E2), dexamethasone (DEX), or anti‐androgen drugs, protein expression of the AT1 receptor and Ang‐I/II was augmented.

Conclusions

The present data suggest that prostatic RAS is overexpressed in HRPC tissue, and expression of its components is influenced by several kinds of hormonal stimulation. Prostate © 2006 Wiley‐Liss, Inc.
Electronic structures of double perovskites Ba2MnMO6 (M = W and Re) from first‐principles studies
Authors: Cheng J. , Yang Z. Q.
Published: February 2006

The electronic structures of double perovskites Ba2MnWO6 and Ba2MnReO6 are studied by using first‐principles linear muffin‐tin orbital method. The ground magnetic phases for the two compounds are found to be antiferromagnetic and ferrimagnetic, respectively, in agreement with experimental results. Barium atoms in both of the compounds show obvious ionic characters while very strong hybridizations are found among the states of Mn 3d–O 2p–W(Re) 5d. Metallic band structure is obtained for Ba2MnReO6 even though on‐site Coulomb interaction (LSDA+U method) is considered for Mn 3d and Re 5d states. A finite energy gap appears in the compound only when spin–orbital coupling on Re ions is also taken into account. This semiconducting band structure can explain well the curve of resistivity versus temperature observed in experiment for ferrimagnetic Ba2MnReO6. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of dielectric screening on the binding energies and diamagnetic susceptibility of a donor in a quantum well wire
Authors: Latha M. , Rajashabala S. , Navaneethakrishnan K.
Published: February 2006

The effect of the dielectric screening on donor binding energies in a quantum wire has been estimated. Since the screening function is shown to be significant in a few phenomena like carrier transport, and not so in a few cases like the donor binding energy calculations, five different screening functions have been used in the calculations to see their relative merits. It is observed that the dielectric function obtained by Resta using the Thomas–Fermi approximation not only gives lower estimates of the ionization energies for all well widths (L ), but also is shown to vary very rapidly with L . The other functions used are those of Hermanson and Vinsome & Richardson. Using the results of the variational calculations for the finite barrier problem, the diamagnetic susceptibility of a donor as a function of L has also been estimated. Though experimental results are not available, we have compared our results for E ion with other theoretical estimates available in the literature. The agreement is found to be good. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of impurities on polaron dynamics in conjugated polymers: Effective potentials
Authors: Lima Matheus Paes , E Silva Geraldo Magela
Published: February 2006

We study the effects of impurities acting on polarons associated with a description of conducting polymers, using a Su–Schrieffer–Heeger‐type Hamiltonian, extended to include an external electric field, Coulomb interactions, and impurities. With the unrestricted time‐dependent Hartree–Fock approximation, we study the interaction between polarons and impurities in conjugated polymers. In polaron dynamics, an impurity acts on a polaron, attracting or repelling it. The character of attraction or repulsion is determined by the polaron charge and the impurity characteristics: donor or acceptor. When we consider a polaron moving on a chain that contains impurities, the polaron can be trapped, passed, or reflected by an impurity. In the present work, the rules that determine the polaron behavior are described by calculating effective potentials due to impurities. Additionally, the case of polarons trapped on impurities is considered. We show that the imprisonment of polarons by impurities could be temporary. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
First principles study of 1,2‐dichlorobenzene adsorption on metallic carbon nanotubes
Authors: Fagan Solange B. , Girão E. C. , Filho J. Mendes , Filho A. G. Souza
Published: February 2006

A systematic study of the structural and electronic properties of a 1,2‐dichlorobenzene (DCB) molecule interacting with metallic single‐wall carbon nanotubes is reported. The calculations were performed through ab initio methods using the SIESTA code. The interaction between DCB and nanotube is observed to depend on the diameter and it is larger for metallic nanotubes when compared with semiconducting. The binding energies are small thus suggesting that the interaction is through a physisorption process. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
On stabilization of nonlinear systems under data rate constraints using output measurements
Authors: De Persis C.
Published: February 2006

We present a contribution to the problem of semi‐global asymptotic stabilization ofnonlinearcontinuous‐time systems underdata rate constraintswhen onlyoutput measurementsare available. We consider systems which are uniformly observable and we point out that the design of an ‘embedded‐observer’ decoder and a controller which semi‐globally stabilize this class of systems under data‐rate constraints requires an appropriate choice of the observer gainandthe data rate. Copyright © 2006 John Wiley & Sons, Ltd.
Velamentous cord insertion into the lower third of the uterus is associated with intrapartum fetal heart rate abnormalities
Authors: Hasegawa J. , Matsuoka R. , Ichizuka K. , Sekizawa A. , Farina A. , Okai T.
Published: February 2006

Objectives

To evaluate the accuracy of sonographic identification of the site of umbilical cord insertion (CI) at 18–20 weeks of gestation, to compare the sensitivities for detection of a velamentous cord insertion (VCI) secondary to a CI into the anterior, posterior or fundal wall, and to compare the intrapartum complications secondary to VCI into the upper, middle or lower third of the uterus.

Methods

As part of the routine ultrasound scan at 18–20 weeks' gestation we evaluated abnormal CI (VCI and marginal CI) and the location of the CI in the uterus in 3446 pregnancies. In cases of abnormal CI, the location of the CI was further classified as being in the upper, middle or lower third of the uterus. After delivery, the placenta and the umbilical cord were examined and intrapartum complications were compared with the location of the CI.

Results

The values for antenatal detection of VCI were: sensitivity, 25 of 40 (62.5%); positive predictive value, 25 of 25 (100%); and negative predictive value, 3406 of 3421 (99.6%). The sensitivity for cases in which the CI was located on the anterior wall was 12 of 13 (92.3%); when it was located on the posterior wall, the sensitivity was 11 of 22 (50.0%); and when it was fundal the sensitivity was 2 of 5 (40.0%). Variable decelerations were frequently observed with a VCI. In lower VCI cases, non‐reassuring fetal heart rate patterns and emergency Cesarean sections occurred with a higher frequency than in cases with upper or middle VCI (P < 0.01). After delivery, the length of the aberrant vessels in cases of VCI by pathologic examination was 3.9 ± 3.3 cm in the upper third, 4.7 ± 4.6 cm in the middle third, and 10.6 ± 6.8 cm in the lower third; thus, the aberrant vessel length was significantly greater when the CI was in the lower third of the uterus (P = 0.024).

Conclusion

We have demonstrated that VCI with a lower CI site and with longer aberrant vessels is associated with various intrapartum complications. This finding has the potential for improving perinatal outcome. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Equivalent MIRID Models
Authors: Maris Gunter , Bechger Timo M.
Published: February 2006

It is shown that in the context of the Model with Internal Restrictions on the Item Difficulties (MIRID), different componential theories about an item set may lead to equivalent models. Furthermore, we provide conditions for the identifiability of the MIRID model parameters, and it will be shown how the MIRID model relates to the Linear Logistic Test Model (LLTM). While it is known that the LLTM is a special case of the MIRID, we show that it is possible to construct an LLTM that encompasses the MIRID. The MIRID model places a bilinear restriction on the item parameters of the Rasch model. It is explained how this fact is used to simplify the results of Bechger, Verhelst, and Verstralen (2001) and Bechger, Verstralen, and Verhelst (2002), and extend their scope to a wider class of models.
Positive Loadings and Factor Correlations from Positive Covariance Matrices
Authors: Krijnen Wim P.
Published: February 2006

In many instances it is reasonable to assume that the population covariance matrix has positive elements. This assumption implies for the single factor analysis model that the loadings and regression weights for best linear factor prediction are positive. For the multiple factor analysis model where each variable loads on a single factor and a hierarchical factor model, it implies that the loadings and the factor correlations are positive. For the latter model it also implies that the regression weights for first- and second-order factor prediction are positive.
Negative Relationships between Abilities
Authors: Broverman Donald M. , Klaiber Edward L.
Published: February 2006

Abilities are usually assumed to exist in a “positive manifold.” Experimental manipulations of physiological variables, however, suggest that negative relationships exist between certain of the neural processes contributing to simple perceptual-motor vs. perceptual-restructuring tasks. First-order correlative evidence of this phenomenon cannot be obtained because the between-individual differences in general ability level tend to exceed the behavioral effects of the intra-individual opposition between neural processes. Also, since statistical removal of the “g” variance induces bipolarity in the remaining variance, the second-order negative correlations are necessarily regarded as artifactual. A combined correlational-experimental approach is suggested to overcome this difficulty.
Optimal Choice of Rater Terms I: Theory
Authors: Elashoff Janet Dixon
Published: February 2006

How can an investigator choose a good team of raters to use for measuring a continuous variable when each available rater produces only dichotomous responses? We formulate an underlying model, define an index of goodness for rater teams in terms of average mean square error of the estimate, develop a new estimator and derive the optimal rater terms. The optimal raters have characteristic curves which are linear in form and satisfy the requirements for a Guttman scale.
Optimal Choice of Rater Teams II: Applications
Authors: Elashoff Janet Dixon , Spiegel Donald E.
Published: February 2006

In a previous paper [Elashoff 1969], we derived optimal rater teams for a particular formulation of the dichotomous rater problem. Here, we describe a computer-based procedure for selecting good rater teams in practice; we apply the procedure to the selection of items for a psychological inventory.
Efficient Estimation in Image Factor Analysis
Authors: Jöreskog K. G.
Published: February 2006

The image factor analytic model (IFA), as related to Guttman’s image theory, is considered as an alternative to the traditional factor analytic model (TFA). One advantage with IFA, as compared with TFA, is that more factors can be extracted without yielding a perfect fit to the observed data. Several theorems concerning the structural properties of IFA are proved and an iterative procedure for finding the maximum likelihood estimates of the parameters of the IFA-model is given. Substantial experience with this method verifies that Heywood cases never occur. Results of an artificial experiment suggest that IFA may be more factorially invariant than TFA under selection of tests from a large battery.
Some Extensions of Image Analysis
Authors: Bentler P. M.
Published: February 2006

A general model for describing the interrelations of common scores is derived. Guttman’s image analysis is a special case. In addition, a new factor model based upon estimation of the person product-moment matrix is described for the case in which the number of variables exceeds the number of persons.
Restricted Ranking
Authors: Norman James E. , David H. A.
Published: February 2006

This paper is a study of certain aspects of restricted ranking, a method intended for use by a panel of m judges evaluating the relative merits of N subjects, candidates for scholarships, awards, etc. Each judge divides the N subjects into R classes so that ni individuals receive a grade i (i = 1, 2, …, R; Σni = N) where the R numbers ni are close to N/R (ni = N/R when N is divisible by R) and are preassigned and the same for all judges. This method is superior in several respects to other likely alternatives. Under the null hypothesis that all nR = N subjects are of equal merit, four tests of significance are developed. The effectiveness of the method is investigated both theoretically by means of the asymptotic relative efficiency and more generally by simulation studies. When the numbers ni are not restricted to values close to or equal to N/R but instead are given values conforming to a normally distributed pattern, the resulting method is known as the Q-sort, so designated by certain investigators in psychotherapy. The simulation studies reveal that restricted ranking is only slightly inferior to complete ranking and generally superior in the cases considered to the Q-sort, although there are likely to be other situations when the latter is superior.
A Newton-Raphson Algorithm for Maximum Likelihood Factor Analysis
Authors: Jennrich Robert I. , Robinson Stephen M.
Published: February 2006

This paper demonstrates the feasibility of using a Newton-Raphson algorithm to solve the likelihood equations which arise in maximum likelihood factor analysis. The algorithm leads to clean easily identifiable convergence and provides a means of verifying that the solution obtained is at least a local maximum of the likelihood function. It is shown that a popular iteration algorithm is numerically unstable under conditions which are encountered in practice and that, as a result, inaccurate solutions have been presented in the literature. The key result is a computationally feasible formula for the second differential of a partially maximized form of the likelihood function. In addition to implementing the Newton-Raphson algorithm, this formula provides a means for estimating the asymptotic variances and covariances of the maximum likelihood estimators.
Least Squares Metric, Unidimensional Unfolding
Authors: Poole Keith T.
Published: February 2006

The partial derivatives of the squared error loss function for the metric unfolding problem have a unique geometry which can be exploited to produce unfolding methods with very desirable properties. This paper details a simple unidimensional unfolding method which uses the geometry of the partial derivatives to find conditional global minima; i.e., one set of points is held fixed and the global minimum is found for the other set. The two sets are then interchanged. The procedure is very robust. It converges to a minimum very quickly from a random or non-random starting configuration and is particularly useful for the analysis of large data sets with missing entries.
Redundancy Analysis for Qualitative Variables
Authors: Israels Abby Z.
Published: February 2006

Redundancy analysis (also called principal components analysis of instrumental variables) is a technique for two sets of variables, one set being dependent of the other. Its aim is maximization of the explained variance of the dependent variables by a linear combination of the explanatory variables. The technique is generalized to qualitative variables; it then gives implicitly a simultaneous ‘optimal’ scaling of the dependent, qualitative variables. Examples are taken from the Dutch Life Situation Survey 1977, using Satisfaction with Life and Happiness as dependent variables. The analysis leads to one well-being scale, defined by the explanatory variables Marital status, Schooling, Income and Activity.
On the Geometric Approach to Multivariate Selection
Authors: Skinner C. J.
Published: February 2006

Multivariate selection can be represented as a linear transformation in a geometric framework. This approach has led to considerable simplification in the study of the effects of selection on factor analysis. In this note this approach is extended to describe the effects of selection on regression analysis and to adjust for the effects of selection using the inverse of the linear transformation.
The Simplex in Pair Comparisons
Authors: Bloxom Bruce
Published: February 2006

A model of individual differences in pair comparisons is developed, assuming the affective values to have a quasi-simplex structure. Procedures for fitting the model to data are suggested. An empirical example is given for one of the procedures.
Departures from Binomial Assumptions in Short-Term Memory Models
Authors: Grams William , van Belle Gerald
Published: February 2006

Experiments in short-term memory usually collect binary data and pool the results of several subjects. The observed pooled proportion of recall is then transformed by the angular transformation to stabilize the variance. In this paper the variance of the transformed proportion is derived and a simple test statistic is obtained to check the validity of the binomial model. Some numerical comparisons for selected poolings are made.
Obtaining Squared Multiple Correlations from a Correlation Matrix which may be Singular
Authors: Tucker Ledyard R , Cooper Lee G. , Meredith William
Published: February 2006

A theorem is presented relating the squared multiple correlation of each measure in a battery with the other measures to the unique generalized inverse of the correlation matrix. This theorem is independent of the rank of the correlation matrix and may be utilized for singular correlation matrices. A coefficient is presented which indicates whether the squared multiple correlation is unity or not. Note that not all measures necessarily have unit squared multiple correlations with the other measures when the correlation matrix is singular. Some suggestions for computations are given for simultaneous determination of squared multiple correlations for all measures.
On Sensitive Rank Tests for Comparing the Effects of Two Treatments on a Single Group
Authors: Ury Hans K.
Published: February 2006

The rank test Rn of Cronholm and Revusky [1965] in effect doubles the number of comparisons carried out in the Mann-Whitney test between “Treated” and “Control” subjects chosen from a single group of n and triples the asymptotic Pitman efficiency against shift alternatives by using a series of n – 1 subexperiments. However, the full series can be too costly or time-consuming. It is shown that j appropriately chosen subexperiments will permit one to make at least j/(j + 1) of the number of comparisons possible under Rn, with large sample efficiency of j/(j + 2) relative to Rn against shift alternatives and small sample efficiency greater than that, j = 2, 3, …, n − 2. The resulting test criterion is a sum of j independent Mann-Whitney test statistics. Its null distribution is tabulated for n ≤ 10 and small sample efficiency comparisons are carried out for n = 10.
The Implications of Convergent and Discriminant Validity Data for Instrument Validation
Authors: Krause Merton S.
Published: February 2006

It seems intuitively compelling to many investigators that measurements, on the same subjects by different methods, purportedly of the same given trait are somehow better evidenced to be mutually valid measurements of that trait to the degree that they are intercorrelated. It is similarly compelling that measurements on the same subjects of purportedly different and uncorrelated traits are somehow better evidenced to be valid measurements to the degree that they are not intercorrelated. Further, a demonstration of hetero-method mono-trait intercorrelation (convergence) jointly with one of hetero-method, or preferably mono-method, hetero-trait independence (discrimination) is more compelling than either single demonstration alone [see Campbell & Fiske, 1959]. I hope to show in what follows that this intuition is misleading unless certain rather demanding prerequisites are satisfied. Then I hope to show that contrary demonstrations are generally too indecisive to consitute validity disconfirmations. Finally, I shall consider some issues in the practical use of the indecisive multitrait-multimethod data.
A Geometrical Analysis of the Unfolding Model: Nondegenerate Solutions
Authors: Davidson J. A.
Published: February 2006

Given the complete set R of rank orders derived from some configuration of n stimulus points in r dimensions in accordance with the unfolding model, a stimulus configuration which generates just these orders will be described as a solution for R. The space is assumed to be Euclidean. Necessary and sufficient conditions are determined for a nondegenerate configuration to be a solution for R. The geometrical conditions which are necessary and sufficient to determine the subset of pairs of opposite orders are also identified and constitute the constraint system for the ordinal vector model.
Some Extensions of Johnson's Hierarchical Clustering Algorithms
Authors: Hubert Lawrence
Published: February 2006

Considerable attention has been given in the psychological literature to techniques of data reduction that partition a set of objects into optimally homogeneous groups. This paper is an attempt to extend the hierarchical partitioning algorithms proposed by Johnson and to emphasize a general connection between these clustering procedures and the mathematical theory of lattices. A goodness-of-fit statistic is first proposed that is invariant under monotone increasing transformations of the basic similarity matrix. This statistic is then applied to three illustrative hierarchical clusterings: two obtained by the Johnson algorithms and one obtained by an algorithm that produces the same chain under hypermonotone increasing transformations of the similarity measures.
A New Solution to the Additive Constant Problem in Metric Multidimensional Scaling
Authors: Cooper Lee G.
Published: February 2006

A new solution to the additive constant problem in metric multidimensional scaling is developed. This solution determines, for a given dimensionality, the additive constant and the resulting stimulus projections on the dimensions of a Euclidean space which minimize the sum of squares of discrepancies between the formal model for metric multidimensional scaling and the original data. A modification of Fletcher-Powell style functional iteration is used to compute solutions. A scale free index of the goodness of fit is developed to aid in selecting solutions of adequate dimensionality from multiple candidates.
Nonmetric Multidimensional Scaling: A Monte Carlo Study of the Basic Parameters
Authors: Sherman Charles R.
Published: February 2006

Metric determinacy of nonmetric multidimensional scaling was investigated as a function of the number of points being scaled, the amount of error in the data being scaled, and the accuracy of estimation of the Minkowski distance function parameters, dimensionality and the r-constant. It was found that nonmetric scaling may provide better models if (1) the true structure is of low dimensionality, (2) the dimensionality of recovered structure is not less than the dimensionality of the true structure, (3) degree of error is low, and (4) the degrees of freedom ratio is greater than about 2.5. It was also found that (5) accurate estimation of the Minkowski constant leads to a better model only if the dimensionality has been properly estimated.
Approximate Methods in Calculating Discriminant Functions
Authors: Beall Geoffrey
Published: February 2006

Approximate methods of solving for discriminant functions have been tried on three sets of data. The principal illustration is the problem of finding a weighted sum of scores, on four psychological tests, so that men and women may be distinguished most clearly. The work starts from the complete solution, due to R. A. Fisher, where it is necessary to solve as many simultaneous equations, dependent on the standard deviations of the tests and their mutual correlations, as there are tests. It is proposed, by way of numerical simplification, that a set of equations be substituted where some one quantity replaces all the correlations. A solution is obtained where the weights to be assigned the tests are very simply expressed in terms of differences between the mean values of tests, the standard deviations of tests, and the said quantity. The difficulty remains of finding an estimate of the arbitrary constant that will give good discrimination. If an optimal solution is made a result is obtained which, in the three sets of data considered, is almost indistinguishable from that yielded by the complete solution. The calculation of this optimal common quantity is, however, itself so considerable that another estimate, previously suggested by R. W. B. Jackson, appears more profitable. This estimate is derived simply from the variability between the total scores for each subject and the variability of each test. Using this estimate, the discriminant functions can be rapidly calculated; the results compare very favorably, in the case of the data considered, with those from the complete solution.
A Graphical Test for the Significance of Differences between Frequencies from different Samples
Authors: Fiske Donald W. , Dunlap Jack W.
Published: February 2006

For testing the significance of differences between frequencies from different samples, an ellipse can easily be constructed on the basis of a formula developed on the assumption that both observed samples are random samples from the same parent population and that the best estimate of the true proportion is the weighted mean proportion of the two samples. The ellipse provides a very rapid method for testing pairs of frequencies.
A Special Review of The American Soldier, Vol. IV
Authors: McCarthy Philip J.
Published: February 2006

Volume IV of The American Solider presents the first complete account of the scale analysis approach of Guttman and the latent structure approach of Lazarsfeld to the problem of attitude measurement. This review has been prepared for the purpose of providing an expository account of the models proposed by Guttman and Lazarsfeld, together with an indication of the places which call for additional clarification and research.
A Square Root Method of Selecting a Minimum Set of Variables in Multiple Regression: I. The Method
Authors: Summerfield A. , Lubin A.
Published: February 2006

An extension of Dwyer's “square root” method has been made to the problem of selecting a minimum set of variables in a multiple regression problem. The square root method of selection differs from the Wherry-Doolittle method primarily in that (1) the computations required are more compact, (2) an F ratio criterion is used which leads to the selection of fewer variables. The method provides solutions for the problems of test selection, item analysis, analysis of variance with disproportionate frequencies, and other problems requiring the rejection of superfluous variables. In a subsequent article a worked example will be given, and the square root and Wherry-Doolittle methods compared.
Effect of Group Heterogeneity on Item Parameters
Authors: Gulliksen Harold
Published: February 2006

Most indexes of item validity and difficulty vary systematically with changes in the mean and variance of the group. Formulas are presented showing how certain item parameters will vary with these alterations in group mean and variance. Item parameters are also suggested which should remain invariant under such changes. These parameters are developed under two different assumptions: first, the assumption that the total distribution of the item ability variable is normal, and, second, that the distribution of the item ability variable for each array of the explicit selection variable is normal.
Intermittent non‐ketotic dicarboxylic aciduria in two siblings with hypoglycaemia: An apparent defect in β‐oxidation of fatty acids
Authors: Naylor E. W. , Mosovich L. L. , Guthrie R. , Evans J. E. , Tieckelmann H.
Published: February 2006

Two siblings with intermittent hypoglycaemia, lethargy and coma associated with fatty infiltration of the liver are reported. Urine contained C6 to C14‐dicarboxylic acids.
Argininosuccinic acid synthetase deficiency in a hamster cell line and its complementation of argininosuccinic aciduria human fibroblasts
Authors: González‐Noriega A. , Verduzco J. , Prieto E. , Velázquez A.
Published: February 2006

Unlike normal human cells, cultured fibroblasts from patients with argininosuccinic aciduria cannot synthesize arginine from citrulline because they have a deficiency of argininosuccinic acid lyase (ASL). We have found that V79, a Chinese hamster cell line, cannot grow on citrulline. Although these cells show a normal uptake of citrulline and have levels of ASL comparable to a human cell line (HeLa) which can grow in citrulline‐containing medium, V79 cells have less than 5% of the argininosuccinic acid synthetase (ASS) activity of HeLa and cannot convert citrulline to argininosuccinate and thence to arginine. When heterokaryocytes are formed between V79 and a human cell line derived from a patient with ASL deficiency, complementation takes place and citrulline is incorporated into cell protein, presumably after having been converted to arginine. This is the first time that a genetic defect of the urea cycle has been corrected in human cells.
Biochemical studies in a patient with defects in the metabolism of acyl‐CoA and sarcosine: Another possible case of glutaric aciduria type II
Authors: Gregersen N. , Kølvraa S. , Rasmussen K. , Christensen E. , Brandt N. J. , Ebbesen F. , Hansen F. H.
Published: February 2006

The clinical and biochemical abnormalities in a neonate, who died in coma accompanied by severe hypoglycaemia at the age of 3 days, are described. The study of the urinary metabolic profiles of organic acids and amino acids revealed that the excretion rates of glutaric acid, isovaleric acid, isovalerylglycine, 3‐hydroxyisovaleric acid and isobutyric acid were very high. Increased excretion rates were also found for 2‐methylbutyric acid, adipic acid, caproylglycine, 5‐hydroxycaproic acid, caproic acid and butyric acid. The amino acid, sarcosine, was excreted in enhanced amounts and the patient had lactic aciduria, whereas the excretion of 3‐hydroxybutyric acid was only moderately increased. This abnormal excretion pattern is consistent with a defect in the metabolism of acyl‐CoAs and sarcosine. Normal activity of glutaryl‐CoA dehydrogenase was found, excluding glutaryl‐CoA dehydrogenase deficiency (glutaric aciduria type I).
Uptake of lysosomal enzymes by human fibroblasts: Lack of uptake of fungal or plant glycosidases in comparison with a mammalian enzyme
Authors: Dooley K. C. , Applegarth D. A.
Published: February 2006

α‐Galactosidase from human placenta was actively taken up by cultured fibroblasts from patients with Fabry's disease whereas the enzyme from the fig was not absorbed. α‐Glucosidase from two microbiological sources,A. fumigatus andA. niger, was not taken up by cultured fibroblasts from patients with Pompe's disease.
Remarks on the Method of Paired Comparisons: I. The Least Squares Solution Assuming Equal Standard Deviations and Equal Correlations
Authors: Mosteller Frederick
Published: February 2006

Thurstone's Case V of the method of paired comparisons assumes equal standard deviations of sensations corresponding to stimuli and zero correlations between pairs of stimuli sensations. It is shown that the assumption of zero correlations can be relaxed to an assumption of equal correlations between pairs with no change in method. Further the usual approach to the method of paired comparisons Case V is shown to lead to a least squares estimate of the stimulus positions on the sensation scale.
The Dimensions of Temperament
Authors: Thurstone L. L.
Published: February 2006

The correlations among the thirteen personality scores yielded by the Guilford schedule for factors STDCR, and the Guilford-Martin schedules for factors GAMIN, and O, Ag, and Co, as reported by Lovell, were factored by the centroid method. The purpose was to see how many factors were represented by the thirteen scores; therefore the test reliabilities were used in the diagonal cells. It was found that the scores represent not more than nine linearly independent factors. The orthogonal factor matrix was rotated to oblique simple structure. Seven of the oblique factors were given tentative interpretation. Two factors were regarded as residual factors because of the small variance which they represent. The seven factors have been named Active, Vigorous, Impulsive, Dominant, Stable, Sociable, and Reflective.
A Note on Correcting for Chance Success in Objective Tests
Authors: Lyerly Samuel B.
Published: February 2006

The conventional scoring formula to “correct for guessing” is derived and is compared with a regression method for scoring which has been recently proposed by Hamilton. It is shown that the usual formula, S = R – W/(n−1), yields a close approximation (correct within one point) to the maximum-likelihood estimate of an individual's “true score” on the test, if we assume that the individual “knows” or “does not know” the answer to each item, that guessing at unknown items is random, and that success at guessing is governed by the binomial law. It is also shown that the usual scoring formula yields an unbiased estimate of the individual's “true score,” when the true score is defined as the mean score over an indefinitely large number of independent attempts at the test or at equivalent (parallel) tests.
Classification by Multivariate Analysis
Authors: Anderson T. W.
Published: February 2006

The problem considered is the use of a set of measurements on an individual to decide from which of several populations he has been drawn. It is assumed that in each population there is a probability distribution of the measurements. Principles for choosing the rule of classification are based on costs of misclassification. Optimum procedures are derived in general terms. If the measurements are normally distributed, the procedures use one discriminant function in the case of two populations and several discriminant functions in the cases of more populations. The numerical example given involves three normal populations.
The Relationship between the Method of Successive Residuals and the Method of Exhaustion
Authors: Layton Wilbur L.
Published: February 2006

The relationship between Horst's method of successive residuals and Gengerelli's method of exhaustion is demonstrated by transforming both methods into L notation. The L notation form is much more efficient computationally.
The Relationship between the Validity of a Single Test and its Contribution to the Predictive Efficiency of a Test Battery
Authors: Horst Paul
Published: February 2006

Typical selection or classification testing programs should provide for improvement of the predictive efficiency of the test battery. Such provision calls for the administration of experimental tests along with the operational battery administration and follow-up analysis to determine the value of the experimental material. It is possible to determine without waiting for criterion data what the validity of the experimental test must be in order to improve the battery validity. The method together with the proof is presented.
An Empirical Verification of the Wherry-Gaylord Iterative Factor Analysis Procedure
Authors: Wherry Robert J. , Campbell Joel T. , Perloff Robert
Published: February 2006

A comparison of the Wherry-Gaylord iterative factor analysis procedure and the Thurstone multiple-group analysis of sub-tests shows that the two methods result in the same factors. The Wherry-Gaylord method has the advantage of giving factor loadings for items. The number of iterations needed can be reduced by doing a factor analysis of sub-tests, re-grouping sub-tests according to factors, and using each group as a starting point for iterations.