The star plot: an alternative display method for multivariate data in the analysis of food and drugs

The star plot (SP) is a method of displaying multivariate data. It can be used to display data with more than two variables. Combined with principal component analysis (PCA), more than two PCs can be displayed in one plane. Different variants of this method are applied to an atomic absorption spectrometry (AAS) data set and to three near infra-red (NIR) spectral data sets. The results show that SP offers an easy way of visualising the multivariate data for food and drugs in a plane, and it is able to help the analyst to identify and to detect different qualities of food and drug composition. Moreover, when an object is added or removed, the PC's must be computed all over again, which is not the case for the SP-plot. The application of SP to the examples presented in the text suggests that the SP approach can be applied as an alternative method for displaying multivariate chemometric data in place of PCA or, to improve visualisation of the results already obtained with PCA.     

Innovative community services for rape victims: an application of multiple case study methodology

A qualitative multiple case study design was used to examine communities across the United States that have developed coordinated community-based programs to assist rape victims. Previous studies have suggested that coordinated community programs help victims obtain needed resources and services. This study provided a follow-up examination of how and why these programs are helpful to rape victims. In-depth interviews were conducted with rape victim advocates, rape crisis center directors, police officers, prosecutors, doctors, nurses, and rape survivors from 22 communities with coordinated programs. A comparison sample of 22 communities with fewer coordinated programs was also obtained. Results indicated that the high coordination communities had three types of programs to address sexual assault: coordinated service programs, interagency training programs, and community-level reform groups. Although not all of these programs directly address service delivery for rape victims, they help create a community culture that is more responsive to victims' needs. The research team and participants developed an explanatory model of why these program are effective in addressing rape victims' needs. This model hypothesizes that coordinated programs reflect an understanding of the multiple contexts of service delivery and embody that knowledge in services that are consistent with victims' needs. Narrative data from the interviews with service providers and rape survivors are used to develop and support this model.     

Analysis of failure times for multiple infections following bone marrow transplantation: an application of the multiple failure time proportional hazards model

We report an application of the proportional hazards model for multiple failure times in a study arising from the Bone Marrow Transplant Database at the University of Minnesota. The study compared the risk of infections after transplantation for patients who received allogeneic bone marrow transplants from unrelated donors (URD) versus related donors (RD). In 249 patients there was a total of 365 infections in 2.5 years of follow-up. The multiple failure time model uses all the data and provides empirical estimates of standard errors that incorporate the within-person dependencies in the data. The estimate of relative risk associated with URD was 1.4 (naive 95 per cent confidence interval 1.14 to 1.73, empirical 1.08 to 1.79), compared to the estimate 1.6 (naive or empirical, 1.1 to 2.1) from the proportional hazards model on 165 first infections only. The multivariate model gives great flexibility in modelling, for example, in accommodating a separate base hazard function for each type of failure and in allowing analysis of intervals between infections as an alternative to analysis of time from a marker event, here transplantation.     

Estimating meiotic exchange patterns from recombination data: an application to humans

We present analytical methods to estimate the recombinational history of chromosomes in a human population. Our analysis, similar to those utilized in Drosophila, can be used to construct meiotic maps based upon crossover frequencies observed in family data. We apply this method of exchange estimation to a population of paternally and maternally inherited chromosomes 21. The patterns of chromosomal exchange estimated by this type of analysis are comparable to those obtained by the more technically difficult method of cytologically counting chiasmata among human male meiotic events (sperm). This type of analysis can be applied to both male and female meiosis, circumventing many technical problems inherent to cytological counting. Moreover, the distribution of exchange locations along a chromosome for each exchange type (i.e., single, double, or triple exchanges) can be examined individually, an advantage compared to examination of genetic maps that only provide a summary of these distributions. We discuss how this analysis can be used to examine various assumptions concerning meiotic exchange in humans and investigate properties of the analysis that contribute to the accuracy of the results.     

A psychoanalytic reinterpretation of the effectiveness of systematic desensitization: Experimental data bearing on the role of merging fantasies.

Subjected 10 women with insect phobias to a variant of systematic desensitization in which a procedure aimed at stimulating a fantasy of "merging with mother" was substituted for muscle relaxation. The procedure consisted of the tachistoscopic subliminal exposure of the verbal stimulus MOMMY AND I ARE ONE during the visualization part of desensitization, whenever the S's anxiety rose above a specified level. A control group of 10 other women with insect phobias underwent the same procedure except that the subliminally exposed message was the neutral stimulus PEOPLE WALKING. On measures of both phobic behavior and anxiety, the experimental group manifested significantly more improvement than the controls. This supports the proposition that (part of) the effectiveness of systematic desensitization resides in its activating unconscious merging fantasies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extent and effect of surface tilt on the data display of the EyeSys videokeratoscope

AIMS: This study examined the occurrence, magnitude, and the consequences of a possible tilt between the corneal surface and optical axis of the EyeSys videokeratoscope. METHODS: Initially, a theoretical model was developed to calculate the angle of tilt. The predictions of the model were verified empirically using a convex conicoid surface and were found to predict the tilt to within 0.5 degree of the actual tilt. The likely effects of the tilt on the corneal power were also examined. The angle of tilt was then measured on the human cornea and the effect of neutralising the tilt on the videokeratoscopic data display was observed. RESULTS: The angle of tilt was found to lie between 1 degree and 6 degrees in a temporal direction. CONCLUSION: When the corneal tilt on the human subjects was neutralised, then a reduction in the nasal/temporal asymmetry was observed.     

Integrative data analysis: The simultaneous analysis of multiple data sets.

There are both quantitative and methodological techniques that foster the development and maintenance of a cumulative knowledge base within the psychological sciences. Most noteworthy of these techniques is meta-analysis, which allows for the synthesis of summary statistics drawn from multiple studies when the original data are not available. However, when the original data can be obtained from multiple studies, many advantages stem from the statistical analysis of the pooled data. The authors define integrative data analysis (IDA) as the analysis of multiple data sets that have been pooled into one. Although variants of IDA have been incorporated into other scientific disciplines, the use of these techniques is much less evident in psychology. In this article the authors present an overview of IDA as it may be applied within the psychological sciences, discuss the relative advantages and disadvantages of IDA, describe analytic strategies for analyzing pooled individual data, and offer recommendations for the use of IDA in practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

COFFEE: an objective function for multiple sequence alignments

MOTIVATION: In order to increase the accuracy of multiple sequence alignments, we designed a new strategy for optimizing multiple sequence alignments by genetic algorithm. We named it COFFEE (Consistency based Objective Function For alignmEnt Evaluation). The COFFEE score reflects the level of consistency between a multiple sequence alignment and a library containing pairwise alignments of the same sequences. RESULTS: We show that multiple sequence alignments can be optimized for their COFFEE score with the genetic algorithm package SAGA. The COFFEE function is tested on 11 test cases made of structural alignments extracted from 3D_ali. These alignments are compared to those produced using five alternative methods. Results indicate that COFFEE outperforms the other methods when the level of identity between the sequences is low. Accuracy is evaluated by comparison with the structural alignments used as references. We also show that the COFFEE score can be used as a reliability index on multiple sequence alignments. Finally, we show that given a library of structure-based pairwise sequence alignments extracted from FSSP, SAGA can produce high-quality multiple sequence alignments. The main advantage of COFFEE is its flexibility. With COFFEE, any method suitable for making pairwise alignments can be extended to making multiple alignments. AVAILABILITY: The package is available along with the test cases through the WWW: http://www. ebi.ac.uk/cedric CONTACT: cedric.notredame@ebi.ac.uk     

The use of multiple imputation for the analysis of missing data.

This article provides a comprehensive review of multiple imputation (MI), a technique for analyzing data sets with missing values. Formally, MI is the process of replacing each missing data point with a set of m > 1 plausible values to generate m complete data sets. These complete data sets are then analyzed by standard statistical software, and the results combined, to give parameter estimates and standard errors that take into account the uncertainty due to the missing data values. This article introduces the idea behind MI, discusses the advantages of MI over existing techniques for addressing missing data, describes how to do MI for real problems, reviews the software available to implement MI, and discusses the results of a simulation study aimed at finding out how assumptions regarding the imputation model affect the parameter estimates provided by MI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Estimating probabilistic choice models from sparse data: A method and an application to groups.

In this article, we present an approach for estimating the parameters of probabilistic choice models for individuals or groups when the amount of data available for each decision-making unit (DMU) is sparse. The approach hinges on the assumption that these parameters vary across DMUs and decisions made by the same DMU in a systematic manner. Furthermore, it is assumed that the systematic variation is dictated by a set of personal or situational variables that are known and observable. We demonstrate that these assumptions allow one to aggregate data across DMUs and yet estimate an idiosyncratic set of parameters for each DMU. A significant aspect of the output of the approach is the ability to assess the relative impact of the personal and situational variables on each DMU's parameter values. As an illustration, the approach is applied to a weighted probability model of group choice proposed by Choffray and Lilien (1980). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multiple regression analysis for categorical data with an illustrative application in personnel selection.

Discusses a unified approach to the analysis of categorical data. The procedure is appropriate whenever 1 set of categorical variables can be regarded as dependent and a 2nd set is identified as predictor variables. The approach is identical to the traditional logit analysis model, but for computational convenience the procedure can be modeled in the more general log-linear framework. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Image presentation in digital radiology: perspectives on the emerging DICOM display function standard and its application

DICOM (Digital Imaging and Communications in Medicine) Working Group XI, formerly called ACR/NEMA (American College of Radiology/National Electrical Manufacturers' Association) Working Group XI, is currently developing a display function standard. The main objective of the standard is to define mathematically a display function for all image presentation systems. As a secondary objective, the standard aims at providing similarity in gray-scale perception for a given image between display systems of different luminance and at facilitating efficient utilization of the available digital input levels of a display system. The design of the display function incorporates the concept of perceptual linearization. The proposed standard applies to monochrome image presentation devices such as cathode ray tube monitor-display controller systems and digital laser image printers. The standard does not eliminate the use of application-specific display functions but rather ensures their effectiveness. Neither does the standard guarantee equal information transfer between image presentation devices with different physical properties; it does, however, from the basis for applying image processing to compensate for such differences.     

一种多缸同步控制算法及应用

现代冶金工业中,多个液压缸同时作用于同一设备的应用越来越多,为了保证多缸的协同运动,除了要求液压执行元件的选型一致外,电气控制的同步控制算法起到了非常重要的作用。同步控制算法是通过软件方法消除多个液压缸之间运动的差异性,弥补由于液压执行元件、载荷分布、管路、变形等因素造成的设备运动位移的不一致。本文以一种连铸机翻转冷床设备为实例,介绍一种适用于多个液压缸配合的电气同步控制算法,对该算法的应用进行了详细说明,并对此方法的特点进行了评述。