Using Profile Analysis via Multidimensional Scaling (PAMS) to identify core profiles from the WMS-III.

Profile Analysis via Multidimensional Scaling (PAMS) is a procedure for extracting latent core profiles in a multitest data set. The PAMS procedure offers several advantages compared with other profile analysis procedures. Most notably, PAMS estimates individual profile weights that reflect the degree to which an individual's observed profile approximates the shape and scatter of latent core profiles. The PAMS procedure was applied to index scores of nonreplicated participants from the standardization sample (N = 1,033) for the Wechsler Memory Scale-Third Edition (D. Tulsky, J. Zhu, & M. F. Ledbetter, 2002). PAMS extracted discrepant visual memory and auditory memory versus working memory core profiles for the complete 16- to 89-year-old sample and discrepant working memory and auditory memory versus working memory core profiles for the 75- to 89-year-old cohort. Implications for use of PAMS in future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inferences from personnel tests and their validity.

[Correction Notice: An erratum for this article was reported in Vol 70(3) of Journal of Applied Psychology (see record 2008-10968-001). On page 238, line 4, the word "each" appears and should be "such." The sentence will, therefore, refer "to the use of such cognitive processes as inductive and deductive reasoning and such characteristics of temperament as emotional stability and self-esteem."] Contends that despite clear definitions in standard sources, psychologists persistently refer to the validity of tests instead of the validity of inferences from test scores. This persistence leads to references to "kinds of validity" when, in fact, there are "kinds of validity analysis strategies" whereby data are collected or generated to determine or defend the extent, degree, or strength of the inference or inferences that can be made from a set of test scores. It is concluded that content validity analysis strategies are appropriate only when the job behavior under scrutiny falls at the observation end of the continuum; when such behavior approaches the abstract end of the continuum, a construct validity analysis strategy is indicated. (5 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implications for social policy of variability in racial groups.

Social policy and federal and state legislation require the use of single cut scores when tests of cognitive ability, knowledge, or skills (CAKS) are used to make high-stakes assessment decisions, such as whether students or employees may be promoted. Rationales offered for the requirement are that cut scores provide objective standards and are fairer than using subjective criteria, such as racial group membership. It is argued that failure to consider threats to statistical conclusion validity, such as differences in variability between groups, obscures the differential impact of using a common cut score as the basis for highstakes decisions. Analyses of 40 Black and White samples revealed that (a) Whites might be considerably advantaged and Blacks might be considerably disadvantaged by the same cut score and (b) depending on where the cut score is set, decisions based on ratios of numbers of Whites numbers of Blacks might be fairer than use of CAKS test cut scores. Implications for assessment practice and social policy are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Observer-independent method for microstructural parcellation of cerebral cortex: A quantitative approach to cytoarchitectonics

We describe a new, observer-independent procedure for identifying boundaries between cortical areas. The method is useful for images obtained from sections which provide microstructural information on the cortical laminar pattern, e.g., Nissl-, myelin-, or immunohistochemically stained sections or receptor autoradiographs. The laminar pattern is represented by profile curves extending from the cortical surface to the white matter boundary. These profiles are constructed from digitized images. Digitization is based on the grey level index (Nissl) or densitometry (myelin, immunohistochemistry, receptor autoradiography). The shapes of neighboring profiles are compared by calculating their distances according to feature vectors extracted from the profiles. Profiles derived from a homogeneous area can be expected to be similar in shape and hence show low distance values between each other. Maximum distances can be found between profiles which lie on opposite sides of a structural boundary. The Mahalanobis distance was found to be more sensitive and to yield greater spatial resolution than other distance measures such as the Euclidean distance. Cell-stained sections of the human neocortex were analyzed. The method not only verified boundaries which had been defined by visual inspection, it also revealed new ones which had not been detected visually. The procedure offers an important supplement to the traditional methods based on visual inspection which, for the first time, is based on quantitative data and therefore offers a new level of reproducibility and observer independence. Anatomical atlases based on this procedure thus provide a new tool for the interpretation of structural data obtained from functional imaging techniques.     

Statistical graphics in pharmacokinetics and pharmacodynamics: a tutorial

OBJECTIVE: To discuss the use of statistical graphics in the analysis of pharmacokinetics and pharmacodynamics data. METHODS: Information on graphic techniques and their application was retrieved from a MEDLINE search (January 1980-March 1997) of the English-language literature and bibliographic reviews of review articles and books. Data used to generate plots were extracted from some new drug applications submitted to the Food and Drug Administration and by simulation. DATA SYNTHESIS: In carrying out data analysis, we should look at data in several ways, construct a number of plots, and do several analyses, letting the results of each step suggest the next. The information from a plot should be relevant to the goals of the analysis. Thus, in choosing a graphic method, it is necessary to match the capabilities of the method to the need in the context of the application. For example, if linear relationships among variables in a set of multidimensional data are relevant, scatter plots such as the pairs plot with smoothing is likely to be more informative than other graphic methods. It is necessary to recognize what kinds of perceived structure are attributable to the data, and what kinds are artifacts of the display technique itself when using graphs for data analysis. CONCLUSIONS: Graphic techniques enable the data analyst to explore data thoroughly, look for patterns and relationships, confirm or disprove the expected, and discover new phenomena. An important element of statistical graphic techniques is flexibility, both in tailoring the analysis to the structure of the data and in responding to patterns that successive steps of analysis uncover. Statistical graphics can and should be used to enhance numeric statistical analyses.     

Functional analysis of linker insertions and point mutations in the alpha-Amy2/54 GA-regulated promoter

First metatarsal fractures are rare because of their thick size and shape. They are to be treated aggressively because of the prolonged disability associated with such fractures. Any injury to the first ray may drastically alter the pattern of normal gait and weight-bearing. Most of the literature regarding such fractures is anecdotal, and there is little in the way of scientific articles that investigate their management. The general consensus for treatment of closed, nondisplaced first metatarsal fractures is to use some form of plaster immobilization. Nevertheless, there is much variation in the literature concerning the length of time patients should be casted. Rigid internal fixation using AO techniques is preferred if open reduction is to be instituted. Long-term complications with first metatarsal fractures are attributed mostly to malunion in the sagittal plane, resulting in a nonplantigrade foot.     

Incremental validity of WISC–III profile elevation, scatter, and shape information for predicting reading and math achievement.

The use of cognitive subtest profiles to hypothesize about children's learning strengths and weaknesses implicitly assumes that subtest profiles are predictive of academic performance. To test this assumption, Wechsler Intelligence Scale for Children—Third Edition (WISC—III) subtest profiles were decomposed into elevation, scatter, and shape components and sequentially regressed onto reading and math achievement scores for 1,118 nonexceptional and 538 exceptional students. Profile evaluation was statistically and practically significant for both exceptional (R?=?.36–.61) and nonexceptional (R?=?.72–.75) students. Profile scatter did not aid in the prediction of achievement. Profile shape accounted for an additional 5%–8% of the variance in achievement measures. It was concluded that using WISC—III subtest scatter and shape to predict academic performance was not supported by the accumulated scientific evidence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A three-dimensional model of the spray forming method

A three-dimensional model has been formulated to calculate the shape of the general preform, using vector calculus. The shape of a rod, tube, plate, or irregular preform can be calculated at given spray forming conditions. The shape of a spray-formed rod was analyzed at various spray forming conditions using the three-dimensional model. The effects of spray forming parameters, such as spray distribution parameters, angular velocity of rotation, withdrawal velocity, spray angle, and eccentric distance on rod shape, were analyzed. The most important parameters affecting the shape of rods are the spray distribution parameters and the withdrawal velocity. The dynamic evolution of rod shape with a stepwise variation of the withdrawal velocity during spray forming was investigated. The effect of a stepwise change of the withdrawal velocity was the same as that of the scanning atomizer. The calculated surface profiles were compared with those of spray-formed 7075 aluminum alloy rods prepared on a pilot scale. The calculated results for the surface profiles were in agreement with those of the spray-formed rods.     

A study on the stability of bronopol in bronopol lotion by ion-paired reversed-phase high performance liquid chromatography

Six patients with avulsion fractures of the metacarpophalangeal joints of the fingers are reported. Operation was performed in all cases. Judging from the operative findings, the radiological assessment of fragment shape is helpful in treatment. Surgery is recommended when the fragment is triangular or rectangular in shape because the fracture involves the articular surface. Conservative treatment is effective if the fragment is round because the articular surface of the joint is not involved in this type of fracture. The avulsed fragment often overlaps the metacarpal head and a collateral ligament injury is likely to be misdiagnosed. It is important to suspect this injury and assess the shape of the whole fragment for a good functional result.     

Markov chain Monte Carlo methods in biostatistics

Appropriate models in biostatistics are often quite complicated. Such models are typically most easily fit using Bayesian methods, which can often be implemented using simulation techniques. Markov chain Monte Carlo (MCMC) methods are an important set of tools for such simulations. We give an overview and references of this rapidly emerging technology along with a relatively simple example. MCMC techniques can be viewed as extensions of iterative maximization techniques, but with random jumps rather than maximizations at each step. Special care is needed when implementing iterative maximization procedures rather than closed-form methods, and even more care is needed with iterative simulation procedures: it is substantially more difficult to monitor convergence to a distribution than to a point. The most reliable implementations of MCMC build upon results from simpler models fit using combinations of maximization algorithms and noniterative simulations, so that the user has a rough idea of the location and scale of the posterior distribution of the quantities of interest under the more complicated model. These concerns with implementation, however, should not deter the biostatistician from using MCMC methods, but rather help to ensure wise use of these powerful techniques.     

ECG pattern recognition and classification using non-linear transformations and neural networks: a review

The most widely used signal in clinical practice is the ECG. ECG conveys information regarding the electrical function of the heart, by altering the shape of its constituent waves, namely the P, QRS, and T waves. Thus, the required tasks of ECG processing are the reliable recognition of these waves, and the accurate measurement of clinically important parameters measured from the temporal distribution of the ECG constituent waves. In this paper, we shall review some current trends on ECG pattern recognition. In particular, we shall review non-linear transformations of the ECG, the use of principal component analysis (linear and non-linear), ways to map the transformed data into n-dimensional spaces, and the use of neural networks (NN) based techniques for ECG pattern recognition and classification. The problems we shall deal with are the QRS/PVC recognition and classification, the recognition of ischemic beats and episodes, and the detection of atrial fibrillation. Finally, a generalised approach to the classification problems in n-dimensional spaces will be presented using among others NN, radial basis function networks (RBFN) and non-linear principal component analysis (NLPCA) techniques. The performance measures of the sensitivity and specificity of these algorithms will also be presented using as training and testing data sets from the MIT-BIH and the European ST-T databases.     

Development and characterization of Nickel–Titanium–Zirconium shape memory alloy for engineering applications

Shape Memory Alloys (SMA) are unique class of alloys which possess various engineering applications. One such SMA is Nickel–Titanium (Nitinol) shape memory alloy. The problem, however with Nickel is that the metal may leach out in form of toxic Ni²⁺ ions. The latter may prove costly when used in various applications. To increase the corrosion resistant properties of Nitinol and to evaluate its shape memory properties, small amount of Zirconium i.e. 5 and 10 at % are added into the existing Nitinol system. Buttons of Nitinol and Nickel–Titanium with Zirconium additions are made using the button arc furnace. For the characterization of the alloys, various techniques including Energy Dispersive Spectroscopy (EDS), Back Scattering Electron (BSE) imaging, Differential Scanning Calorimetry (DSC) have been performed. The work conducted reveals that addition of Zirconium in Nitinol has marked influence on microstructure, shape memory properties, transformation temperature, hardness values, and corrosion properties of the alloy.     

The efficacy of radiofrequency lesioning of the cervical spinal dorsal root ganglion in a double blinded randomized study: no difference between 40 degrees C and 67 degrees C treatments

Marfan syndrome (MFS) is an autosomal dominant trait due to mutations in the fibrillin gene (FBN1). The MFS expressivity is variable, and its diagnosis relies completely on clinical criteria. Atypical cases and Marfan-like (marfanoid) clinical presentations are commonly found. The metacarpophalangeal pattern profile (MCPP), a radiological method in which the 19 tubular hand bones are assessed, has been used in the diagnosis of various syndromes. To investigate whether the MCPP was adequate to discriminate between MFS and Marfan-like subjects, we studied 38 patients who were referred to our service because they had an MFS diagnosis, diagnostic hypothesis, or differential diagnosis or had arachnodactyly with dolichostenomelia. Two groups were formed: 1) MFS: 21 patients with a mean age of 18.3 (10.8 S.D.) years and 2) Marfan-like syndromes: 16 patients who did not meet the current criteria, with a mean age of 14.6 (4.6 S.D.) years. The MCPP was performed in each case following the classical technique, and a characteristic mean profile was obtained for group I (MFS), with Z scores ranging from 0.69 to 2.73 (1.80+/-0.50; mean+/-S.D.). In group I, three cases had no correlation with the typical MFS pattern. In group II, three cases had an MFS pattern. The correlation with the mean MCPP of MFS permitted the differential diagnosis of MFS and marfanoid syndromes with 86% sensitivity, 81% specificity, and 86% positive and 81% negative predictive values. The results suggest that MCPP can be used effectively as an auxiliary tool in the nosology of these conditions and, because there is no change in MCPP with age, can be helpful in early diagnosis.     

Predicting quadriceps muscle activity during gait with an automatic rule determination method

It has been suggested that control using a skill-based expert system can be applicable to gait restoration. Rule-based systems have several advantages for this application: they generate a fast response (they are not computationally intensive) and they are easy to comprehend and implement. A major problem with using such systems is the inability of users to determine its rules. In this study, an automatic method for obtaining the production rules from a set of examples is described. The rule base was automatically induced from a model which used external sensor signals as inputs and electromyogram (EMG) patterns as outputs. The method is based on the minimization of entropy. A production rule estimated the muscle activity pattern using the sensor information. The algorithm was tested using data recorded from six able-bodied individuals during ground level walking, with and without ankle-foot orthoses. The data showed that gait variability will increase in able-bodied subjects when the motion of ankle joints is restricted, thus, providing a good test for generalization. The experimental results illustrate performance of the production rule that estimates quadriceps muscle group activity pattern for ground level walking in able-bodied subjects.     

Improving the calculation of interdiffusion coefficients

Least-squares spline interpolation techniques are reviewed and presented as a mathematical tool for noise reduction and interpolation of diffusion profiles. Numerically simulated diffusion profiles were interpolated using a sixth-order spline. The spline fit data were successfully used in conjunction with the Boltzmann-Matano treatment to compute the interdiffusion coefficient, demonstrating the usefulness of splines as a numerical tool for such calculations. Simulations conducted on noisy data indicate that the technique can extract the correct diffusivity data given compositional data that contain only three digits of information and are contaminated with a noise level of 0.001. Splines offer a reproducible and reliable alternative to graphical evaluation of the slope of a diffusion profile, which is used in the Boltzmann-Matano treatment. Hence, use of splines reduces the numerical errors associated with calculation of interdiffusion coefficients from raw diffusion profile data.     

Reply to Professor Bechtoldt's critique.

Presents a reply regarding Bechtoldt's critique (see record 1960-06754-001) of the article by Haggard et al. (see record 1960-00131-001). True, many of the comments in his section on "Factor Analytic Techniques" are interesting and informative--and generally corrective--but they are also essentially irrelevant to our paper and its purpose. There is clear difference of opinion as to whether, when, or what factor analytic techniques should be used in particular cases. Some of Bechtoldt's remarks in his sections entitled "Direct Correlation Methods'and "Concluding Remarks" call for more specific comment, primarily because I think he misses the point from time to time. Bechtoldt has us on the ropes when he cites the statement "with the procedures discussed thus far, it is not possible to form groups around such a priori profiles." We should have said "not practicable" (instead of using the too strong term "not possible") to indicate that, for the majority of research workers, these procedures are not possible from a practical point of view. In his concluding paragraph, he appears to chide us (following his phrase "other technically questionable discussions") for possibly suggesting "the testing of statistical hypotheses using sets of related observations." We took pains to observe that, although multivariate data can be analyzed properly only by the appropriate multivariate statistical techniques, approximate produres for pattern analytic studies are available which utilize most of the information in the data without violating certain important statistical assumptions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simultaneous dorsal luxation of metacarpophalangeal joints of the four long fingers. Apropos of a case

PURPOSE OF THE STUDY: The authors describe an unusual case of simultaneous dorsal dislocation of the metacarpophalangeal joints of the index, long, ring, and little fingers. MATERIAL AND METHODS: A 67-year-old man fell on the pavement when walking, striking his outstretched left hand. A diagnosis of multiple fingers dislocation was easily clinically and radiologically established. The wound was cleaned and the dislocations reduced by closed manipulation at the operating room. RESULT: The patient had an uneventful recovery, after a three week period of immobilization with a dorsal extension block splint. DISCUSSION AND CONCLUSIONS: The use of art extension block splint allowed a minimal healing delay for disrupted volar metacarpophalangeal structures, allowing a good fingers range of motion.     

Composite finger metacarpophalangeal joint reconstruction in combined second and third free toe-to-hand transfers

Composite metacarpophalangeal joint reconstruction using the toe proximal phalanx and the metacarpal head, with a capsular repair, is an option during free toe transfer procedures for absent fingers. Eleven composite metacarpophalangeal finger joint reconstructions were performed in four patients concurrent with combined second and third toe-to-hand transfer. The average follow-up period was 5 years. Postoperative assessment included range of motion, stability, radiographic changes, and pain. The average range of motion was 52 degrees, average ulnar stress deviation was 14 degrees. No patients complained of pain. Composite metacarpophalangeal joint reconstruction should be considered in free toe-to-hand procedures when metacarpal head articular cartilage is preserved.