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Sample records for numa rede unidimensional

  1. NUMA: A Northern Paiute History.

    ERIC Educational Resources Information Center

    Inter-Tribal Council of Nevada, Reno.

    One in a series of four histories of native Nevadans, this volume presents the story of the Northern Paiute people, or Numa, who lived, hunted, and travelled in the Great Basin area which occupies one-third of present day Nevada and parts of Oregon, Idaho, and California. Based on interviews with tribal elders and research conducted at numerous…

  2. Progress in Characterizing Strictly Unidimensional IRT Representations

    DTIC Science & Technology

    1990-11-29

    covariance in (2) continues to be negative if one omits the conditioning on 0, because Xj is "nearly sufficient" for 0. In the Rasch model for example , (2) is...practice: the Rasch , 2PL and 3PL models . Key Words: strict unidimensionality, essential unidimensionality, useful models , condi- tional association...quantities determine the latent structure of the test. ’It is possible in principle to decide whether the Rasch model holds, without more items, using

  3. Unidimensional Interpretations for Multidimensional Test Items

    ERIC Educational Resources Information Center

    Kahraman, Nilufer

    2013-01-01

    This article considers potential problems that can arise in estimating a unidimensional item response theory (IRT) model when some test items are multidimensional (i.e., show a complex factorial structure). More specifically, this study examines (1) the consequences of model misfit on IRT item parameter estimates due to unintended minor item-level…

  4. Parallel Analysis with Unidimensional Binary Data

    ERIC Educational Resources Information Center

    Weng, Li-Jen; Cheng, Chung-Ping

    2005-01-01

    The present simulation investigated the performance of parallel analysis for unidimensional binary data. Single-factor models with 8 and 20 indicators were examined, and sample size (50, 100, 200, 500, and 1,000), factor loading (.45, .70, and .90), response ratio on two categories (50/50, 60/40, 70/30, 80/20, and 90/10), and types of correlation…

  5. Are Utilitarian/Deontological Preferences Unidimensional?

    PubMed Central

    Laakasuo, Michael; Sundvall, Jukka

    2016-01-01

    Utilitarian versus deontological inclinations have been studied extensively in the field of moral psychology. However, the field has been lacking a thorough psychometric evaluation of the most commonly used measures. In this paper, we examine the factorial structure of an often used set of 12 moral dilemmas purportedly measuring utilitarian/deontological moral inclinations. We ran three different studies (and a pilot) to investigate the issue. In Study 1, we used standard Exploratory Factor Analysis and Schmid-Leimann (g factor) analysis; results of which informed the a priori single-factor model for our second study. Results of Confirmatory Factor Analysis in Study 2 were replicated in Study 3. Finally, we ran a weak invariance analysis between the models of Study 2 and 3, concluding that there is no significant difference between factor loading in these studies. We find reason to support a single-factor model of utilitarian/deontological inclinations. In addition, certain dilemmas have consistent error covariance, suggesting that this should be taken into consideration in future studies. In conclusion, three studies, pilot and an invariance analysis, systematically suggest the following. (1) No item needs to be dropped from the scale. (2) There is a unidimensional structure for utilitarian/deontological preferences behind the most often used dilemmas in moral psychology, suggesting a single latent cognitive mechanism. (3) The most common set of dilemmas in moral psychology can be successfully used as a unidimensional measure of utilitarian/deontological moral inclinations, but would benefit from using weighted averages over simple averages. (4) Consideration should be given to dilemmas describing infants. PMID:27582721

  6. The organizational learning survey: a re-evaluation of unidimensionality.

    PubMed

    Goh, Swee C; Quon, Tony K; Cousins, J Bradley

    2007-12-01

    An earlier study by Chakrabarty and Rogé evaluated the dimensionality of the Organizational Learning Survey for assessing the learning capability of organizations developed by Goh and Richards. In this paper, the survey was re-evaluated for unidimensionality using both exploratory and confirmatory factor analysis. Retaining 18 of the original 21 items was sufficient to establish unidimensionality. A number of different confirmatory models validated the unidimensional measurement model on two independent data sets. Implications for further empirical research using this inventory are discussed.

  7. Identification and characterization of novel NuMA isoforms

    SciTech Connect

    Wu, Jin; Xu, Zhe; He, Dacheng; Lu, Guanting

    2014-11-21

    Highlights: • Seven NuMA isoforms generated by alternative splicing were categorized into 3 groups: long, middle and short. • Both exons 15 and 16 in long NuMA were “hotspot” for alternative splicing. • Lower expression of short NuMA was observed in cancer cells compared with nonneoplastic controls. • Distinct localization pattern of short isoforms indicated different function from that of long and middle NuMA. - Abstract: The large nuclear mitotic apparatus (NuMA) has been investigated for over 30 years with functions related to the formation and maintenance of mitotic spindle poles during mitosis. However, the existence and functions of NuMA isoforms generated by alternative splicing remains unclear. In the present work, we show that at least seven NuMA isoforms (categorized into long, middle and short groups) generated by alternative splicing from a common NuMA mRNA precursor were discovered in HeLa cells and these isoforms differ mainly at the carboxyl terminus and the coiled-coil domains. Two “hotspot” exons with molecular mass of 3366-nt and 42-nt tend to be spliced during alternative splicing in long and middle groups. Furthermore, full-length coding sequences of long and middle NuMA obtained by using fusion PCR were constructed into GFP-tagged vector to illustrate their cellular localization. Long NuMA mainly localized in the nucleus with absence from nucleoli during interphase and translocated to the spindle poles in mitosis. Middle NuMA displayed the similar cell cycle-dependent distribution pattern as long NuMA. However, expression of NuMA short isoforms revealed a distinct subcellular localization. Short NuMA were present in the cytosol during the whole cycle, without colocalization with mitotic apparatus. These results have allowed us tentatively to explore a new research direction for NuMA’s various functions.

  8. The Effect of NUMA Tunings on CPU Performance

    NASA Astrophysics Data System (ADS)

    Hollowell, Christopher; Caramarcu, Costin; Strecker-Kellogg, William; Wong, Antonio; Zaytsev, Alexandr

    2015-12-01

    Non-Uniform Memory Access (NUMA) is a memory architecture for symmetric multiprocessing (SMP) systems where each processor is directly connected to separate memory. Indirect access to other CPU's (remote) RAM is still possible, but such requests are slower as they must also pass through that memory's controlling CPU. In concert with a NUMA-aware operating system, the NUMA hardware architecture can help eliminate the memory performance reductions generally seen in SMP systems when multiple processors simultaneously attempt to access memory. The x86 CPU architecture has supported NUMA for a number of years. Modern operating systems such as Linux support NUMA-aware scheduling, where the OS attempts to schedule a process to the CPU directly attached to the majority of its RAM. In Linux, it is possible to further manually tune the NUMA subsystem using the numactl utility. With the release of Red Hat Enterprise Linux (RHEL) 6.3, the numad daemon became available in this distribution. This daemon monitors a system's NUMA topology and utilization, and automatically makes adjustments to optimize locality. As the number of cores in x86 servers continues to grow, efficient NUMA mappings of processes to CPUs/memory will become increasingly important. This paper gives a brief overview of NUMA, and discusses the effects of manual tunings and numad on the performance of the HEPSPEC06 benchmark, and ATLAS software.

  9. The Puzzling Unidimensionality of DSM-5 Substance Use Disorder Diagnoses

    PubMed Central

    MacCoun, Robert J.

    2013-01-01

    There is a perennial expert debate about the criteria to be included or excluded for the DSM diagnoses of substance use dependence. Yet analysts routinely report evidence for the unidimensionality of the resulting checklist. If in fact the checklist is unidimensional, the experts are wrong that the criteria are distinct, so either the experts are mistaken or the reported unidimensionality is spurious. I argue for the latter position, and suggest that the traditional reflexive measurement model is inappropriate for the DSM; a formative measurement model would be a more accurate characterization of the institutional process by which the checklist is created, and a network or causal model would be a more appropriate foundation for a scientifically grounded diagnostic system. PMID:24324446

  10. Essential Unidimensionality Examination for Multicomponent Scales: An Interrelationship Decomposition Approach

    ERIC Educational Resources Information Center

    Raykov, Tenko; Pohl, Steffi

    2013-01-01

    A procedure for examining essential unidimensionality in multicomponent measuring instruments is discussed. The method is based on an application of latent variable modeling and is concerned with the extent to which a common factor for all components of a given scale accounts for their correlations. The approach provides point and interval…

  11. Bayesian Estimation of Multi-Unidimensional Graded Response IRT Models

    ERIC Educational Resources Information Center

    Kuo, Tzu-Chun

    2015-01-01

    Item response theory (IRT) has gained an increasing popularity in large-scale educational and psychological testing situations because of its theoretical advantages over classical test theory. Unidimensional graded response models (GRMs) are useful when polytomous response items are designed to measure a unified latent trait. They are limited in…

  12. Application of Unidimensional Item Response Theory Models to Multidimensional Data.

    ERIC Educational Resources Information Center

    Drasgow, Fritz; Parsons, Charles K.

    The effects of a multidimensional latent trait space on estimation of item and person parameters by the computer program LOGIST are examined. Several item pools were simulated that ranged from truly unidimensional to an inconsequential general latent trait. Item pools with intermediate levels of prepotency of the general latent trait were also…

  13. Delimiting Coefficient a from Internal Consistency and Unidimensionality

    ERIC Educational Resources Information Center

    Sijtsma, Klaas

    2015-01-01

    I discuss the contribution by Davenport, Davison, Liou, & Love (2015) in which they relate reliability represented by coefficient a to formal definitions of internal consistency and unidimensionality, both proposed by Cronbach (1951). I argue that coefficient a is a lower bound to reliability and that concepts of internal consistency and…

  14. Essential Unidimensionality Examination for Multicomponent Scales: An Interrelationship Decomposition Approach

    ERIC Educational Resources Information Center

    Raykov, Tenko; Pohl, Steffi

    2013-01-01

    A procedure for examining essential unidimensionality in multicomponent measuring instruments is discussed. The method is based on an application of latent variable modeling and is concerned with the extent to which a common factor for all components of a given scale accounts for their correlations. The approach provides point and interval…

  15. Delimiting Coefficient a from Internal Consistency and Unidimensionality

    ERIC Educational Resources Information Center

    Sijtsma, Klaas

    2015-01-01

    I discuss the contribution by Davenport, Davison, Liou, & Love (2015) in which they relate reliability represented by coefficient a to formal definitions of internal consistency and unidimensionality, both proposed by Cronbach (1951). I argue that coefficient a is a lower bound to reliability and that concepts of internal consistency and…

  16. Developing an Essentially Unidimensional Test with Cognitively Designed Items

    ERIC Educational Resources Information Center

    Bryant, Damon U.; Wooten, William

    2006-01-01

    The purpose of this study was to demonstrate how cognitive and measurement principles can be integrated to create an essentially unidimensional test. Two studies were conducted. In Study 1, test questions were created by using the feature integration theory of attention to develop a cognitive model of performance and then manipulating complexity…

  17. Modification of Stout's Procedure for Assessing Latent Trait Unidimensionality.

    ERIC Educational Resources Information Center

    Nandakumar, Ratna

    The effectiveness of Stout's procedure for assessing latent trait unidimensionality was studied. Strong empirical evidence of the utility of the statistical test in a variety of settings is provided. The procedure was modified to correct for increased bias, and a new algorithm to determine the size of assessment sub-tests was used. The following…

  18. Bayesian Estimation of Multi-Unidimensional Graded Response IRT Models

    ERIC Educational Resources Information Center

    Kuo, Tzu-Chun

    2015-01-01

    Item response theory (IRT) has gained an increasing popularity in large-scale educational and psychological testing situations because of its theoretical advantages over classical test theory. Unidimensional graded response models (GRMs) are useful when polytomous response items are designed to measure a unified latent trait. They are limited in…

  19. Critical Path-Based Thread Placement for NUMA Systems

    SciTech Connect

    Su, C Y; Li, D; Nikolopoulos, D S; Grove, M; Cameron, K; de Supinski, B R

    2011-11-01

    Multicore multiprocessors use a Non Uniform Memory Architecture (NUMA) to improve their scalability. However, NUMA introduces performance penalties due to remote memory accesses. Without efficiently managing data layout and thread mapping to cores, scientific applications, even if they are optimized for NUMA, may suffer performance loss. In this paper, we present algorithms and a runtime system that optimize the execution of OpenMP applications on NUMA architectures. By collecting information from hardware counters, the runtime system directs thread placement and reduces performance penalties by minimizing the critical path of OpenMP parallel regions. The runtime system uses a scalable algorithm that derives placement decisions with negligible overhead. We evaluate our algorithms and runtime system with four NPB applications implemented in OpenMP. On average the algorithms achieve between 8.13% and 25.68% performance improvement compared to the default Linux thread placement scheme. The algorithms miss the optimal thread placement in only 8.9% of the cases.

  20. Robustness of the Polytomous IRT Model to Violations of the Unidimensionality Assumption.

    ERIC Educational Resources Information Center

    Dawadi, Bhaskar R.

    The robustness of the polytomous Item Response Theory (IRT) model to violations of the unidimensionality assumption was studied. A secondary purpose was to provide guidelines to practitioners to help in deciding whether to use an IRT model to analyze their data. In a simulation study, the unidimensionality assumption was deliberately violated by…

  1. Exploring the Robustness of a Unidimensional Item Response Theory Model with Empirically Multidimensional Data

    ERIC Educational Resources Information Center

    Anderson, Daniel; Kahn, Joshua D.; Tindal, Gerald

    2017-01-01

    Unidimensionality and local independence are two common assumptions of item response theory. The former implies that all items measure a common latent trait, while the latter implies that responses are independent, conditional on respondents' location on the latent trait. Yet, few tests are truly unidimensional. Unmodeled dimensions may result in…

  2. The Use of Unidimensional Item Parameter Estimates of Multidimensional Items in Adaptive Testing.

    ERIC Educational Resources Information Center

    Ackerman, Terry A.

    The purpose of this study was to investigate the effect of using multidimensional items in a computer adaptive test (CAT) setting which assumes a unidimensional item response theory (IRT) framework. Previous research has suggested that the composite of multidimensional abilities being estimated by a unidimensional IRT model is not constant…

  3. Assessing the Unidimensionality of Psychological Scales: Using Multiple Criteria from Factor Analysis

    ERIC Educational Resources Information Center

    Slocum-Gori, Suzanne L.; Zumbo, Bruno D.

    2011-01-01

    Whenever one uses a composite scale score from item responses, one is tacitly assuming that the scale is dominantly unidimensional. Investigating the unidimensionality of item response data is an essential component of construct validity. Yet, there is no universally accepted technique or set of rules to determine the number of factors to retain…

  4. Exploring Unidimensional Proficiency Classification Accuracy from Multidimensional Data in a Vertical Scaling Context

    ERIC Educational Resources Information Center

    Kroopnick, Marc Howard

    2010-01-01

    When Item Response Theory (IRT) is operationally applied for large scale assessments, unidimensionality is typically assumed. This assumption requires that the test measures a single latent trait. Furthermore, when tests are vertically scaled using IRT, the assumption of unidimensionality would require that the battery of tests across grades…

  5. Exploring Unidimensional Proficiency Classification Accuracy from Multidimensional Data in a Vertical Scaling Context

    ERIC Educational Resources Information Center

    Kroopnick, Marc Howard

    2010-01-01

    When Item Response Theory (IRT) is operationally applied for large scale assessments, unidimensionality is typically assumed. This assumption requires that the test measures a single latent trait. Furthermore, when tests are vertically scaled using IRT, the assumption of unidimensionality would require that the battery of tests across grades…

  6. Empirical Memory-Access Cost Models in Multicore NUMA Architectures

    SciTech Connect

    McCormick, Patrick S.; Braithwaite, Ryan Karl; Feng, Wu-chun

    2011-01-01

    Data location is of prime importance when scheduling tasks in a non-uniform memory access (NUMA) architecture. The characteristics of the NUMA architecture must be understood so tasks can be scheduled onto processors that are close to the task's data. However, in modern NUMA architectures, such as AMD Magny-Cours and Intel Nehalem, there may be a relatively large number of memory controllers with sockets that are connected in a non-intuitive manner, leading to performance degradation due to uninformed task-scheduling decisions. In this paper, we provide a method for experimentally characterizing memory-access costs for modern NUMA architectures via memory latency and bandwidth microbenchmarks. Using the results of these benchmarks, we propose a memory-access cost model to improve task-scheduling decisions by scheduling tasks near the data they need. Simple task-scheduling experiments using the memory-access cost models validate the use of empirical memory-access cost models to significantly improve program performance.

  7. Choice and response time processes in the identification and categorization of unidimensional stimuli.

    PubMed

    Lacouture, Yves; Marley, A A J

    2004-10-01

    Lacouture and Marley (1991, 1995, 2001) have successfully modeled the probabilities of correct responses and the mean correct response times (RTs) in unidimensional absolute identification tasks for various stimulus ranges and stimulus/response set sizes, for individual and group data. These fits include those to a set of phenomena often referred to as end-anchor effects. A revised model, with the independent accumulator decision process replaced by a leaky competing accumulator decision process, fits the probabilities of correct responses and the full distributions of RTs in unidimensional absolute identification. The revised model is also applied successfully to a particular class of unidimensional categorization tasks. We discuss possible extensions for handling sequential effects in unidimensional absolute identification, and other extensions of the given class of categorization tasks that are of potential empirical and theoretical importance as a supplement to the study of multidimensional absolute identification tasks.

  8. A FORTRAN Program for Assessing Unidimensionality of Binary Data Using Holland and Rosenbaum's Methodology.

    ERIC Educational Resources Information Center

    Nandakumar, Ratna

    1993-01-01

    The methodology of P. E. Holland and P. R. Rosenbaum (1986) to assess unidimensionality of binary data is outlined and illustrated through a simulation with 36 items for 2,000 examinees. How to interpret the results is discussed. (SLD)

  9. Rae1 interaction with NuMA is required for bipolar spindle formation

    PubMed Central

    Wong, Richard W.; Blobel, Günter; Coutavas, Elias

    2006-01-01

    In eukaryotic cells, the faithful segregation of daughter chromosomes during cell division depends on formation of a microtubule (MT)-based bipolar spindle apparatus. The Nuclear Mitotic Apparatus protein (NuMA) is recruited from interphase nuclei to spindle MTs during mitosis. The carboxy terminal domain of NuMA binds MTs, allowing a NuMA dimer to function as a “divalent” crosslinker that bundles MTs. The messenger RNA export factor, Rae1, also binds to MTs. Lowering Rae1 or increasing NuMA levels in cells results in spindle abnormalities. We have identified a mitotic-specific interaction between Rae1 and NuMA and have explored the relationship between Rae1 and NuMA in spindle formation. We have mapped a specific binding site for Rae1 on NuMA that would convert a NuMA dimer to a “tetravalent” crosslinker of MTs. In mitosis, reducing Rae1 or increasing NuMA concentration would be expected to alter the valency of NuMA toward MTs; the “density” of NuMA-MT crosslinks in these conditions would be diminished, even though a threshold number of crosslinks sufficient to stabilize aberrant multipolar spindles may form. Consistent with this interpretation, we found that coupling NuMA overexpression to Rae1 overexpression or coupling Rae1 depletion to NuMA depletion prevented the formation of aberrant spindles. Likewise, we found that overexpression of the specific Rae1-binding domain of NuMA in HeLa cells led to aberrant spindle formation. These data point to the Rae1–NuMA interaction as a critical element for normal spindle formation in mitosis. PMID:17172455

  10. Cell cycle-dependent SUMO-1 conjugation to nuclear mitotic apparatus protein (NuMA)

    SciTech Connect

    Seo, Jae Sung; Kim, Ha Na; Kim, Sun-Jick; Bang, Jiyoung; Kim, Eun-A; Sung, Ki Sa; Yoon, Hyun-Joo; Yoo, Hae Yong; Choi, Cheol Yong

    2014-01-03

    Highlights: •NuMA is modified by SUMO-1 in a cell cycle-dependent manner. •NuMA lysine 1766 is the primary target site for SUMOylation. •SUMOylation-deficient NuMA induces multiple spindle poles during mitosis. •SUMOylated NuMA induces microtubule bundling. -- Abstract: Covalent conjugation of proteins with small ubiquitin-like modifier 1 (SUMO-1) plays a critical role in a variety of cellular functions including cell cycle control, replication, and transcriptional regulation. Nuclear mitotic apparatus protein (NuMA) localizes to spindle poles during mitosis, and is an essential component in the formation and maintenance of mitotic spindle poles. Here we show that NuMA is a target for covalent conjugation to SUMO-1. We find that the lysine 1766 residue is the primary NuMA acceptor site for SUMO-1 conjugation. Interestingly, SUMO modification of endogenous NuMA occurs at the entry into mitosis and this modification is reversed after exiting from mitosis. Knockdown of Ubc9 or forced expression of SENP1 results in impairment of the localization of NuMA to mitotic spindle poles during mitosis. The SUMOylation-deficient NuMA mutant is defective in microtubule bundling, and multiple spindles are induced during mitosis. The mitosis-dependent dynamic SUMO-1 modification of NuMA might contribute to NuMA-mediated formation and maintenance of mitotic spindle poles during mitosis.

  11. Cell cycle-regulated membrane binding of NuMA contributes to efficient anaphase chromosome separation.

    PubMed

    Zheng, Zhen; Wan, Qingwen; Meixiong, Gerry; Du, Quansheng

    2014-03-01

    Accurate and efficient separation of sister chromatids during anaphase is critical for faithful cell division. It has been proposed that cortical dynein-generated pulling forces on astral microtubules contribute to anaphase spindle elongation and chromosome separation. In mammalian cells, however, definitive evidence for the involvement of cortical dynein in chromosome separation is missing. It is believed that dynein is recruited and anchored at the cell cortex during mitosis by the α subunit of heterotrimeric G protein (Gα)/mammalian homologue of Drosophila Partner of Inscuteable/nuclear mitotic apparatus (NuMA) ternary complex. Here we uncover a Gα/LGN-independent lipid- and membrane-binding domain at the C-terminus of NuMA. We show that the membrane binding of NuMA is cell cycle regulated-it is inhibited during prophase and metaphase by cyclin-dependent kinase 1 (CDK1)-mediated phosphorylation and only occurs after anaphase onset when CDK1 activity is down-regulated. Further studies indicate that cell cycle-regulated membrane association of NuMA underlies anaphase-specific enhancement of cortical NuMA and dynein. By replacing endogenous NuMA with membrane-binding-deficient NuMA, we can specifically reduce the cortical accumulation of NuMA and dynein during anaphase and demonstrate that cortical NuMA and dynein contribute to efficient chromosome separation in mammalian cells.

  12. Dimensions of "unidimensional" ratings of pain and emotions in patients with chronic musculoskeletal pain.

    PubMed

    Huber, Alexa; Suman, Anna Lisa; Rendo, Carmela Anna; Biasi, Giovanni; Marcolongo, Roberto; Carli, Giancarlo

    2007-08-01

    The use of unidimensional scales to measure pain intensity has been criticised because of the multidimensional nature of pain. We conducted multiple linear regression analyses to determine which dimensions of pain--sensory versus affective--predicted scores on unidimensional scales measuring pain intensity and emotions in 109 Italian women suffering from chronic, non-malignant musculoskeletal pain. We then compared the results with earlier findings in two groups of cancer patients suffering from acute post-operative pain and chronic cancer-related pain, respectively. Age, physical capacity and scores on the multidimensional affect and pain survey (MAPS) were used to predict patients' ratings on one visual analogue scale (VAS) and three numerical rating scales (NRS) measuring pain intensity, anxiety and depressed mood. Unidimensional pain intensity ratings were predicted better from sensory than from affective pain predictors, and the affective predictors made no unique contribution (NRS), or only a very small one (VAS). Both sensory and emotional pain aspects were unique predictors of NRS anxiety and depression. Therefore, in contrast to earlier findings in two different types of cancer patients, in subjects affected by chronic non-malignant musculoskeletal pain, the scores on unidimensional pain intensity scales mainly reflect sensory pain dimensions, supporting the discriminant validity of the NRS and VAS used. However, the patients had some difficulty in distinguishing between sensory and emotional information. For this reason, several unidimensional scales to rate pain intensity and emotions separately should be used to obtain a complete picture of the status and needs of any given patient.

  13. The Effects of Multidimensional Polytomous Response Data on Unidimensional Many-FACET Rasch Model Parameter Estimates.

    ERIC Educational Resources Information Center

    Wang, Shudong; Wang, Ning

    When categorical responses were simulated from a Multidimensional Many-FACETS Rasch Compensatory Model (MMFRCM), the effects of ability, task difficulty, and step difficulty estimates with the unidimensional Many-FACETS Rasch Model (MFRM; Linacre, 1999) were examined in terms of three error indexes, average absolute difference (AAD), bias, and…

  14. On Reporting IRT Ability Scores When the Test Is Not Unidimensional.

    ERIC Educational Resources Information Center

    Dirir, Mohamed A.; Sinclair, Norma

    The purpose of this study was to examine the effect of test dimensionality on the stability of examinee ability estimates and item response theory (IRT) based score reports. A simulation procedure based on W. F. Stout's Essential Unidimensionality was used to generate test data with one dominant trait for the whole test and three minor traits…

  15. The Greatest Lower Bound to the Reliability of a Test and the Hypothesis of Unidimensionality

    ERIC Educational Resources Information Center

    Berge, Jos M. F. Ten; Socan, Gregor

    2004-01-01

    To assess the reliability of congeneric tests, specifically designed reliability measures have been proposed. This paper emphasizes that such measures rely on a unidimensionality hypothesis, which can neither be confirmed nor rejected when there are only three test parts, and will invariably be rejected when there are more than three test parts.…

  16. The Asymptotic Distribution of Ability Estimates: Beyond Dichotomous Items and Unidimensional IRT Models

    ERIC Educational Resources Information Center

    Sinharay, Sandip

    2015-01-01

    The maximum likelihood estimate (MLE) of the ability parameter of an item response theory model with known item parameters was proved to be asymptotically normally distributed under a set of regularity conditions for tests involving dichotomous items and a unidimensional ability parameter (Klauer, 1990; Lord, 1983). This article first considers…

  17. Effect of Violating Unidimensional Item Response Theory Vertical Scaling Assumptions on Developmental Score Scales

    ERIC Educational Resources Information Center

    Topczewski, Anna Marie

    2013-01-01

    Developmental score scales represent the performance of students along a continuum, where as students learn more they move higher along that continuum. Unidimensional item response theory (UIRT) vertical scaling has become a commonly used method to create developmental score scales. Research has shown that UIRT vertical scaling methods can be…

  18. Georg Rasch and Benjamin Wright's Struggle with the Unidimensional Polytomous Model with Sufficient Statistics

    ERIC Educational Resources Information Center

    Andrich, David

    2016-01-01

    This article reproduces correspondence between Georg Rasch of The University of Copenhagen and Benjamin Wright of The University of Chicago in the period from January 1966 to July 1967. This correspondence reveals their struggle to operationalize a unidimensional measurement model with sufficient statistics for responses in a set of ordered…

  19. A Class of Multidimensional IRT Models for Testing Unidimensionality and Clustering Items

    ERIC Educational Resources Information Center

    Bartolucci, Francesco

    2007-01-01

    We illustrate a class of multidimensional item response theory models in which the items are allowed to have different discriminating power and the latent traits are represented through a vector having a discrete distribution. We also show how the hypothesis of unidimensionality may be tested against a specific bidimensional alternative by using a…

  20. Effect of Violating Unidimensional Item Response Theory Vertical Scaling Assumptions on Developmental Score Scales

    ERIC Educational Resources Information Center

    Topczewski, Anna Marie

    2013-01-01

    Developmental score scales represent the performance of students along a continuum, where as students learn more they move higher along that continuum. Unidimensional item response theory (UIRT) vertical scaling has become a commonly used method to create developmental score scales. Research has shown that UIRT vertical scaling methods can be…

  1. A Comparison of Unidimensional and Multidimensional IRT Approaches to Test Information in a Test Battery.

    ERIC Educational Resources Information Center

    Chang, Yu-Wen; Davison, Mark L.

    Standard errors and bias of unidimensional and multidimensional ability estimates were compared in a factorial, simulation design with two item response theory (IRT) approaches, two levels of test correlation (0.42 and 0.63), two sample sizes (500 and 1,000), and a hierarchical test content structure. Bias and standard errors of subtest scores…

  2. The Greatest Lower Bound to the Reliability of a Test and the Hypothesis of Unidimensionality

    ERIC Educational Resources Information Center

    Berge, Jos M. F. Ten; Socan, Gregor

    2004-01-01

    To assess the reliability of congeneric tests, specifically designed reliability measures have been proposed. This paper emphasizes that such measures rely on a unidimensionality hypothesis, which can neither be confirmed nor rejected when there are only three test parts, and will invariably be rejected when there are more than three test parts.…

  3. Development and Validation of a Unidimensional Maltreatment Scale in the Add Health Data Set

    ERIC Educational Resources Information Center

    Marszalek, Jacob M.; Hamilton, Jessica L.

    2012-01-01

    Four maltreatment items were examined from Wave III (N = 13,516) of the National Longitudinal Study of Adolescent Health. Item analysis, confirmatory factor analysis, cross-validation, reliability estimates, and convergent validity coefficients strongly supported the validity of using the four items as a unidimensional composite. Implications for…

  4. Performance of Parallel Analysis in Retrieving Unidimensionality in the Presence of Binary Data

    ERIC Educational Resources Information Center

    Tran, Ulrich S.; Formann, Anton K.

    2009-01-01

    Parallel analysis has been shown to be suitable for dimensionality assessment in factor analysis of continuous variables. There have also been attempts to demonstrate that it may be used to uncover the factorial structure of binary variables conforming to the unidimensional normal ogive model. This article provides both theoretical and empirical…

  5. Assessing Model Data Fit of Unidimensional Item Response Theory Models in Simulated Data

    ERIC Educational Resources Information Center

    Kose, Ibrahim Alper

    2014-01-01

    The purpose of this paper is to give an example of how to assess the model-data fit of unidimensional IRT models in simulated data. Also, the present research aims to explain the importance of fit and the consequences of misfit by using simulated data sets. Responses of 1000 examinees to a dichotomously scoring 20 item test were simulated with 25…

  6. Investigating the Practical Consequences of Model Misfit in Unidimensional IRT Models.

    PubMed

    Crişan, Daniela R; Tendeiro, Jorge N; Meijer, Rob R

    2017-09-01

    In this article, the practical consequences of violations of unidimensionality on selection decisions in the framework of unidimensional item response theory (IRT) models are investigated based on simulated data. The factors manipulated include the severity of violations, the proportion of misfitting items, and test length. The outcomes that were considered are the precision and accuracy of the estimated model parameters, the correlations of estimated ability ([Formula: see text]) and number-correct ([Formula: see text]) scores with the true ability ([Formula: see text]), the ranks of the examinees and the overlap between sets of examinees selected based on either [Formula: see text], [Formula: see text], or [Formula: see text] scores, and the bias in criterion-related validity estimates. Results show that the [Formula: see text] values were unbiased by violations of unidimensionality, but their precision decreased as multidimensionality and the proportion of misfitting items increased; the estimated item parameters were robust to violations of unidimensionality. The correlations between [Formula: see text], [Formula: see text], and [Formula: see text] scores, the agreement between the three selection criteria, and the accuracy of criterion-related validity estimates are all negatively affected, to some extent, by increasing levels of multidimensionality and the proportion of misfitting items. However, removing the misfitting items only improved the results in the case of severe multidimensionality and large proportion of misfitting items, and deteriorated them otherwise.

  7. Development and Validation of a Unidimensional Maltreatment Scale in the Add Health Data Set

    ERIC Educational Resources Information Center

    Marszalek, Jacob M.; Hamilton, Jessica L.

    2012-01-01

    Four maltreatment items were examined from Wave III (N = 13,516) of the National Longitudinal Study of Adolescent Health. Item analysis, confirmatory factor analysis, cross-validation, reliability estimates, and convergent validity coefficients strongly supported the validity of using the four items as a unidimensional composite. Implications for…

  8. Circular Unidimensional Scaling: A New Look at Group Differences in Interest Structure

    ERIC Educational Resources Information Center

    Armstrong, Patrick Ian; Hubert, Lawrence; Rounds, James

    2003-01-01

    The fit of J. L. Holland's (1959, 1997) RIASEC model to U.S. racial-ethnic groups was assessed using circular unidimensional scaling. Samples of African American, Asian American, Caucasian American and Hispanic American high school students and employed adults who completed either the UNIACT Interest Inventory (K. B. Swaney, 1995) or the Strong…

  9. NuMA localization, stability, and function in spindle orientation involve 4.1 and Cdk1 interactions

    PubMed Central

    Seldin, Lindsey; Poulson, Nicholas D.; Foote, Henry P.; Lechler, Terry

    2013-01-01

    The epidermis is a multilayered epithelium that requires asymmetric divisions for stratification. A conserved cortical protein complex, including LGN, nuclear mitotic apparatus (NuMA), and dynein/dynactin, plays a key role in establishing proper spindle orientation during asymmetric divisions. The requirements for the cortical recruitment of these proteins, however, remain unclear. In this work, we show that NuMA is required to recruit dynactin to the cell cortex of keratinocytes. NuMA's cortical recruitment requires LGN; however, LGN interactions are not sufficient for this localization. Using fluorescence recovery after photobleaching, we find that the 4.1-binding domain of NuMA is important for stabilizing its interaction with the cell cortex. This is functionally important, as loss of 4.1/NuMA interaction results in spindle orientation defects, using two distinct assays. Furthermore, we observe an increase in cortical NuMA localization as cells enter anaphase. Inhibition of Cdk1 or mutation of a single residue in NuMA mimics this effect. NuMA's anaphase localization is independent of LGN and 4.1 interactions, revealing two distinct mechanisms responsible for NuMA cortical recruitment at different stages of mitosis. This work highlights the complexity of NuMA localization and reveals the importance of NuMA cortical stability for productive force generation during spindle orientation. PMID:24109598

  10. NuMA Phosphorylation by Aurora-A Orchestrates Spindle Orientation.

    PubMed

    Gallini, Sara; Carminati, Manuel; De Mattia, Fabiola; Pirovano, Laura; Martini, Emanuele; Oldani, Amanda; Asteriti, Italia Anna; Guarguaglini, Giulia; Mapelli, Marina

    2016-02-22

    Spindle positioning is essential for tissue morphogenesis and homeostasis. The signaling network synchronizing spindle placement with mitotic progression relies on timely recruitment at the cell cortex of NuMA:LGN:Gαi complexes, in which NuMA acts as a receptor for the microtubule motor Dynein. To study the implication of Aurora-A in spindle orientation, we developed protocols for the partial inhibition of its activity. Under these conditions, in metaphase NuMA and Dynein accumulate abnormally at the spindle poles and do not reach the cortex, while the cortical distribution of LGN remains unperturbed. FRAP experiments revealed that Aurora-A governs the dynamic exchange between the cytoplasmic and the spindle pole-localized pools of NuMA. We show that Aurora-A phosphorylates directly the C terminus of NuMA on three Ser residues, of which Ser1969 determines the dynamic behavior and the spindle orientation functions of NuMA. Most interestingly, we identify a new microtubule-binding domain of NuMA, which does not overlap with the LGN-binding motif. Our study demonstrates that in metaphase the direct phosphorylation of NuMA by Aurora-A controls its cortical enrichment, and that this is the major event underlying the spindle orientation functions of Aurora-A in transformed and non-transformed cells in culture. Phosphorylation of NuMA by Aurora-A does not affect its affinity for microtubules or for LGN but rather determines the mobility of the protein at the spindle poles. The finding that NuMA can associate concomitantly with LGN and microtubules suggests that its microtubule-binding activity contributes to anchor Dynein-loaded microtubule +TIPs at cortical sites with LGN.

  11. Memphis: Finding and Fixing NUMA-related Performance Problems on Multi-core Platforms

    SciTech Connect

    McCurdy, Collin B; Vetter, Jeffrey S

    2010-01-01

    Until recently, most high-end scientific applications have been immune to performance problems caused by Non-Uniform Memory Access (NUMA). However, current trends in micro-processor design are pushing NUMA to smaller and smaller scales. This paper examines the current state of NUMA and makes several contributions. First, we summarize the performance problems that NUMA can present for multithreaded applications and describe methods of addressing them. Second, we demonstrate that NUMA can indeed be a significant problem for scientific applications, showing that it can mean the difference between an application scaling perfectly and failing to scale at all. Third, we describe, in increasing order of usefulness, three methods of using hardware performance counters to aid in finding NUMA-related problems. Finally, we introduce Memphis, a data-centric toolset that uses Instruction Based Sampling to help pinpoint problematic memory accesses, and demonstrate how we used it to improve the performance of several production-level codes - HYCOM, XGC1 and CAM - by 13%, 23% and 24% respectively.

  12. A Revised Modified Parallel Analysis (RMPA) for the Construction of Unidimensional Item Pools

    DTIC Science & Technology

    1993-07-01

    that the measures based on PC, FA and one parameter IRT (the Rasch model ) are outperformed by methods quantifying deviation from multi-parameter IRT...correlation matrix with the corresponding eigenvalue extracted from a "parallel" matrix generated by a unidimensional and locally independent model . Revised...psychological testing has caused a revolution in this domain. These new models enable researchers and test users to solve efficiently otherwise intractable

  13. The nuclear mitotic apparatus (NuMA) protein: localization and dynamics in human oocytes, fertilization and early embryos.

    PubMed

    Alvarez Sedó, Cristian; Schatten, Heide; Combelles, Catherine M; Rawe, Vanesa Y

    2011-06-01

    The oocyte's meiotic spindle is a dynamic structure that relies on microtubule organization and regulation by centrosomes. Disorganization of centrosomal proteins, including the nuclear mitotic apparatus (NuMA) protein and the molecular motor complex dynein/dynactin, can lead to chromosomal instability and developmental abnormalities. The present study reports the distribution and function of these proteins in human oocytes, zygotes and early embryos. A total of 239 oocytes, 90 zygotes and discarded embryos were fixed and analyzed with confocal microscopy for NuMA and dynactin distribution together with microtubules and chromatin. Microtubule-associated dynein-dependent transport functions were explored by inhibiting phosphatase and ATPase activity with sodium-orthovanadate (SOV). At germinal vesicle (GV) stages, NuMA was dispersed across the nucleoplasm. After GV breaks down, NuMA became cytoplasmic before localizing at the spindle poles in metaphase I and II oocytes. Aberrant NuMA localization patterns were found during oocyte in vitro maturation. After fertilization, normal and abnormal pronuclear stage zygotes and embryos displayed translocation of NuMA to interphase nuclei. SOV treatment for up to 2 h induced lower maturation rates with chromosomal scattering and ectopic localization of NuMA. Accurate distribution of NuMA is important for oocyte maturation, zygote and embryo development in humans. Proper assembly of NuMA is likely necessary for bipolar spindle organization and human oocyte developmental competence.

  14. Noninvasive assessment of alcoholic liver disease using unidimensional transient elastography (Fibroscan®)

    PubMed Central

    Lupsor-Platon, Monica; Badea, Radu

    2015-01-01

    Unidimensional transient elastography (TE) is a noninvasive technique, which has been increasingly used in the assessment of diffuse liver diseases. This paper focuses on reviewing the existing data on the use of TE in the diagnosis of fibrosis and in monitoring disease progression in alcoholic liver disease, on the factors that may influence the result of fibrosis prediction, and last but not least, on its potential use in assessing the steatosis degree. Therefore, this field is far from being exhausted and deserves more attention. Further studies are required, on large groups of biopsied patients, in order to find answers to all the remaining questions in this field. PMID:26576080

  15. Perhaps Unidimensional Is Not Unidimensional

    ERIC Educational Resources Information Center

    Dodds, Pennie; Rae, Babette; Brown, Scott

    2012-01-01

    Miller (1956) identified his famous limit of 7 plus or minus 2 items based in part on absolute identification--the ability to identify stimuli that differ on a single physical dimension, such as lines of different length. An important aspect of this limit is its independence from perceptual effects and its application across all stimulus types.…

  16. Perhaps Unidimensional Is Not Unidimensional

    ERIC Educational Resources Information Center

    Dodds, Pennie; Rae, Babette; Brown, Scott

    2012-01-01

    Miller (1956) identified his famous limit of 7 plus or minus 2 items based in part on absolute identification--the ability to identify stimuli that differ on a single physical dimension, such as lines of different length. An important aspect of this limit is its independence from perceptual effects and its application across all stimulus types.…

  17. Children's Depression Inventory: A unidimensional factor structure for American Indian and Alaskan native youth.

    PubMed

    Scott, Walter D; Clapp, Joshua; Mileviciute, Inga; Mousseau, Alicia

    2016-01-01

    Given that American Indian and Alaskan Native (AI/AN) youth are at increased risk for a variety of depression-related outcomes and may experience depression uniquely, the fact that the factor structure of the Children's Depression Inventory (CDI; Kovacs, 1992) is unknown for these populations represents a significant obstacle. In Study 1 with an AI youth sample, we conducted confirmatory factor analyses and failed to find support for either of the 2 predominant CDI multifactor models (Craighead, Smucker, Craighead, & Ilardi, 1998; Kovacs, 1992). In subsequent exploratory structural equation modeling, we found the most support for a unidimensional factor structure. In Study 2, using confirmatory modeling with independent AI/AN youth samples, we found further support for this unidimensional model. Finally, in Study 3, we found support across AI/AN groups varying in gender and age for measurement invariance with respect to both factor structure and factor loadings. Overall, for these AI/AN youth populations, our findings support the practice of calculating total CDI scores, and they suggest a unique construction of the depression experience. (c) 2016 APA, all rights reserved).

  18. Assessing item fit for unidimensional item response theory models using residuals from estimated item response functions.

    PubMed

    Haberman, Shelby J; Sinharay, Sandip; Chon, Kyong Hee

    2013-07-01

    Residual analysis (e.g. Hambleton & Swaminathan, Item response theory: principles and applications, Kluwer Academic, Boston, 1985; Hambleton, Swaminathan, & Rogers, Fundamentals of item response theory, Sage, Newbury Park, 1991) is a popular method to assess fit of item response theory (IRT) models. We suggest a form of residual analysis that may be applied to assess item fit for unidimensional IRT models. The residual analysis consists of a comparison of the maximum-likelihood estimate of the item characteristic curve with an alternative ratio estimate of the item characteristic curve. The large sample distribution of the residual is proved to be standardized normal when the IRT model fits the data. We compare the performance of our suggested residual to the standardized residual of Hambleton et al. (Fundamentals of item response theory, Sage, Newbury Park, 1991) in a detailed simulation study. We then calculate our suggested residuals using data from an operational test. The residuals appear to be useful in assessing the item fit for unidimensional IRT models.

  19. How to conduct research on burnout: advantages and disadvantages of a unidimensional approach in burnout research

    PubMed Central

    Brenninkmeijer, V; VanYperen, N

    2003-01-01

    When conducting research on burnout, it may be difficult to decide whether one should report results separately for each burnout dimension or whether one should combine the dimensions. Although the multidimensionality of the burnout concept is widely acknowledged, for research purposes it is sometimes convenient to regard burnout as a unidimensional construct. This article deals with the question of whether and when it may be appropriate to treat burnout as a unidimensional variable, and presents a decision rule to distinguish between people high and low in burnout. To develop a guideline for obtaining a dichotomous measure of burnout, the scores on the Utrecht Burnout Scale (UBOS) of 44 well functioning individuals were compared with the scores of 29 individuals diagnosed as suffering from burnout. Based on these data, the authors recommend the "exhaustion + 1" criterion for research in non-clinical populations. Following this criterion, individuals can be considered as burnt out when they report, compared to a norm group, high emotional exhaustion, in combination with high depersonalisation or low personal accomplishment. The criterion may be used to estimate the percentage in a sample of individuals in a state of burnout. PMID:12782742

  20. Prevendo a atividade solar através de redes neurais nebulosas

    NASA Astrophysics Data System (ADS)

    Martin, V. A. F.; Poppe, P. C. R.

    2003-08-01

    Atualmente, a integração de redes neurais com técnicas da Matemática Nebulosa (Fuzzy Sets), tem sido usada robustamente para fazer previsões em vários sistemas físicos. Este trabalho representa uma continuidade da contribuição apresentada anteriormente durante a XXVIIa Reunião Anual da SAB, onde exploramos a aplicação de redes neurais para previsões futuras de séries temporais. Para este, enfatizamos o uso da técnica ANFIS (Adaptative Neuro-Fuzzy Inference System), que consiste em uma rede do tipo back-propagation, onde os dados são processados em uma camada intermediária, tendo numa camada de saída, os dados numéricos. Para que a previsão seja feita com sucesso utilizando-se técnicas matemáticas adequadas, é fundamental a existência de uma série razoavelmente longa de modo que a dinâmica contida nesta possa ser melhor extraída pela rede neural. Nesse sentido, foram utilizados novamente os dados históricos das manchas do Sol (1818-2002) afim de verificar o comportamento futuro da atividade solar (Ciclos de Schawbe) a partir da técnica descrita acima. Previsões realizadas para o ciclo anterior (n.22, máximo de 158,5 em julho de 1989), bem como para o atual (n.23, máximo de 153 em setembro de 2000), apontam valores bastante coerentes com os publicados na literatura, levando em consideração, respectivamente, as barras de erros associadas: 166+/-18 e 160+/-14. Para o próximo ciclo de Schawbe (2006-2017), nossa previsão aponta o valor de 172+/-23 como máximo para o primeiro semestre de 2011 (Abril +/- 3 meses). A ANFIS acompanha de maneira satisfatória o movimento das séries estudadas durante o treinamento e durante a verificação (menor dispersão das funções de pertinência), com erro absoluto inferior a 20 por cento.

  1. Katanin p80, NuMA and cytoplasmic dynein cooperate to control microtubule dynamics.

    PubMed

    Jin, Mingyue; Pomp, Oz; Shinoda, Tomoyasu; Toba, Shiori; Torisawa, Takayuki; Furuta, Ken'ya; Oiwa, Kazuhiro; Yasunaga, Takuo; Kitagawa, Daiju; Matsumura, Shigeru; Miyata, Takaki; Tan, Thong Teck; Reversade, Bruno; Hirotsune, Shinji

    2017-01-12

    Human mutations in KATNB1 (p80) cause severe congenital cortical malformations, which encompass the clinical features of both microcephaly and lissencephaly. Although p80 plays critical roles during brain development, the underlying mechanisms remain predominately unknown. Here, we demonstrate that p80 regulates microtubule (MT) remodeling in combination with NuMA (nuclear mitotic apparatus protein) and cytoplasmic dynein. We show that p80 shuttles between the nucleus and spindle pole in synchrony with the cell cycle. Interestingly, this striking feature is shared with NuMA. Importantly, p80 is essential for aster formation and maintenance in vitro. siRNA-mediated depletion of p80 and/or NuMA induced abnormal mitotic phenotypes in cultured mouse embryonic fibroblasts and aberrant neurogenesis and neuronal migration in the mouse embryonic brain. Importantly, these results were confirmed in p80-mutant harboring patient-derived induced pluripotent stem cells and brain organoids. Taken together, our findings provide valuable insights into the pathogenesis of severe microlissencephaly, in which p80 and NuMA delineate a common pathway for neurogenesis and neuronal migration via MT organization at the centrosome/spindle pole.

  2. Katanin p80, NuMA and cytoplasmic dynein cooperate to control microtubule dynamics

    PubMed Central

    Jin, Mingyue; Pomp, Oz; Shinoda, Tomoyasu; Toba, Shiori; Torisawa, Takayuki; Furuta, Ken’ya; Oiwa, Kazuhiro; Yasunaga, Takuo; Kitagawa, Daiju; Matsumura, Shigeru; Miyata, Takaki; Tan, Thong Teck; Reversade, Bruno; Hirotsune, Shinji

    2017-01-01

    Human mutations in KATNB1 (p80) cause severe congenital cortical malformations, which encompass the clinical features of both microcephaly and lissencephaly. Although p80 plays critical roles during brain development, the underlying mechanisms remain predominately unknown. Here, we demonstrate that p80 regulates microtubule (MT) remodeling in combination with NuMA (nuclear mitotic apparatus protein) and cytoplasmic dynein. We show that p80 shuttles between the nucleus and spindle pole in synchrony with the cell cycle. Interestingly, this striking feature is shared with NuMA. Importantly, p80 is essential for aster formation and maintenance in vitro. siRNA-mediated depletion of p80 and/or NuMA induced abnormal mitotic phenotypes in cultured mouse embryonic fibroblasts and aberrant neurogenesis and neuronal migration in the mouse embryonic brain. Importantly, these results were confirmed in p80-mutant harboring patient-derived induced pluripotent stem cells and brain organoids. Taken together, our findings provide valuable insights into the pathogenesis of severe microlissencephaly, in which p80 and NuMA delineate a common pathway for neurogenesis and neuronal migration via MT organization at the centrosome/spindle pole. PMID:28079116

  3. Cell Division: NuMA Bears the Load in the Spindle.

    PubMed

    Maiato, Helder; Pereira, António J

    2017-08-07

    The mitotic spindle bears the load of chromosomes during mitosis, but how this load is distributed across the spindle is unclear. A new study shows that load distribution in the spindle is confined and requires the microtubule cross-linking protein NuMA. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. An IRT Approach to Constructing and Scoring Pairwise Preference Items Involving Stimuli on Different Dimensions: The Multi-Unidimensional Pairwise-Preference Model

    ERIC Educational Resources Information Center

    Stark, Stephen; Chernyshenko, Oleksandr S.; Drasgow, Fritz

    2005-01-01

    This article proposes an item response theory (IRT) approach to constructing and scoring multidimensional pairwise preference items. Individual statements are administered and calibrated using a unidimensional single-stimulus model. Tests are created by combining multidimensional items with a small number of unidimensional pairings needed to…

  5. NuMA is a major acceptor of poly(ADP-ribosyl)ation by tankyrase 1 in mitosis

    PubMed Central

    2005-01-01

    Tankyrase 1 is a PARP [poly(ADP-ribose) polymerase] that localizes to multiple subcellular sites, including telomeres and mitotic centrosomes. Previous studies demonstrated that cells deficient in tankyrase 1 suffered a block in resolution of sister telomeres and arrested in early anaphase [Dynek and Smith (2004) Science 304, 97–100]. This phenotype was dependent on the catalytic PARP activity of tankyrase 1. To identify critical acceptors of PARsylation [poly(ADP-ribosyl)ation] by tankyrase 1 in mitosis, tankyrase 1 immunoprecipitates were analysed for associated PARsylated proteins. We identified NuMA (nuclear mitotic apparatus protein) as a major acceptor of poly(ADP-ribose) from tankyrase 1 in mitosis. We showed by immunofluorescence and immunoprecipitation that association between tankyrase 1 and NuMA increases dramatically at the onset of mitosis, concomitant with PARsylation of NuMA. Knockdown of tankyrase 1 by siRNA (small interfering RNA) eliminates PARsylation of NuMA in mitosis, confirming tankyrase 1 as the PARP responsible for this modification. However, even in the absence of tankyrase 1 and PARsylation, NuMA localizes to spindle poles. By contrast, siRNA knockdown of NuMA results in complete loss of tankyrase 1 from spindle poles. We discuss our result in terms of a model where PARsylation of NuMA by tankyrase 1 in mitosis could play a role in sister telomere separation and/or mitotic progression. PMID:16076287

  6. A Comparison of Estimation Methods for a Multi-unidimensional Graded Response IRT Model

    PubMed Central

    Kuo, Tzu-Chun; Sheng, Yanyan

    2016-01-01

    This study compared several parameter estimation methods for multi-unidimensional graded response models using their corresponding statistical software programs and packages. Specifically, we compared two marginal maximum likelihood (MML) approaches (Bock-Aitkin expectation-maximum algorithm, adaptive quadrature approach), four fully Bayesian algorithms (Gibbs sampling, Metropolis-Hastings, Hastings-within-Gibbs, blocked Metropolis), and the Metropolis-Hastings Robbins-Monro (MHRM) algorithm via the use of IRTPRO, BMIRT, and MATLAB. Simulation results suggested that, when the intertrait correlation was low, these estimation methods provided similar results. However, if the dimensions were moderately or highly correlated, Hastings-within-Gibbs had an overall better parameter recovery of item discrimination and intertrait correlation parameters. The performances of these estimation methods with different sample sizes and test lengths are also discussed. PMID:27375545

  7. Experimental study on all-fiber-based unidimensional continuous-variable quantum key distribution

    NASA Astrophysics Data System (ADS)

    Wang, Xuyang; Liu, Wenyuan; Wang, Pu; Li, Yongmin

    2017-06-01

    We experimentally demonstrated an all-fiber-based unidimensional continuous-variable quantum key distribution (CV QKD) protocol and analyzed its security under collective attack in realistic conditions. A pulsed balanced homodyne detector, which could not be accessed by eavesdroppers, with phase-insensitive efficiency and electronic noise, was considered. Furthermore, a modulation method and an improved relative phase-locking technique with one amplitude modulator and one phase modulator were designed. The relative phase could be locked precisely with a standard deviation of 0.5° and a mean of almost zero. Secret key bit rates of 5.4 kbps and 700 bps were achieved for transmission fiber lengths of 30 and 50 km, respectively. The protocol, which simplified the CV QKD system and reduced the cost, displayed a performance comparable to that of a symmetrical counterpart under realistic conditions. It is expected that the developed protocol can facilitate the practical application of the CV QKD.

  8. Unidimensionality of the Chinese version of the Foreign Language Reading Anxiety Scale.

    PubMed

    Hsiao, Tsung-Yuan

    2002-12-01

    Previous research showed the Foreign Language Reading Anxiety Scale is reliable and valid for assessing reading anxiety in groups of American college students beginning study of French, Japanese, or Russian. Because Saito, Horwitz, and Garza (1999) reported that reading anxiety tends to vary with the target language, the present investigation examined the factorial validity of the Chinese version of the scale in college students of English as a foreign language in Taiwan, Confirmatory factor analysis with maximum likelihood method supports the unidimensionality of the scale, which is reliable and valid for eliciting reading anxiety of Chinese college foreign language learners and for predicting their global language performance. This study suggests exploring how language proficiency, culture, and topic familiarity may be related to such anxiety.

  9. Validation of the UNESP-Botucatu unidimensional composite pain scale for assessing postoperative pain in cattle.

    PubMed

    de Oliveira, Flávia Augusta; Luna, Stelio Pacca Loureiro; do Amaral, Jackson Barros; Rodrigues, Karoline Alves; Sant'Anna, Aline Cristina; Daolio, Milena; Brondani, Juliana Tabarelli

    2014-09-06

    The recognition and measurement of pain in cattle are important in determining the necessity for and efficacy of analgesic intervention. The aim of this study was to record behaviour and determine the validity and reliability of an instrument to assess acute pain in 40 cattle subjected to orchiectomy after sedation with xylazine and local anaesthesia. The animals were filmed before and after orchiectomy to record behaviour. The pain scale was based on previous studies, on a pilot study and on analysis of the camera footage. Three blinded observers and a local observer assessed the edited films obtained during the preoperative and postoperative periods, before and after rescue analgesia and 24 hours after surgery. Re-evaluation was performed one month after the first analysis. Criterion validity (agreement) and item-total correlation using Spearman's coefficient were employed to refine the scale. Based on factor analysis, a unidimensional scale was adopted. The internal consistency of the data was excellent after refinement (Cronbach's α coefficient = 0.866). There was a high correlation (p < 0.001) between the proposed scale and the visual analogue, simple descriptive and numerical rating scales. The construct validity and responsiveness were confirmed by the increase and decrease in pain scores after surgery and rescue analgesia, respectively (p < 0.001). Inter- and intra-observer reliability ranged from moderate to very good. The optimal cut-off point for rescue analgesia was > 4, and analysis of the area under the curve (AUC = 0.963) showed excellent discriminatory ability. The UNESP-Botucatu unidimensional pain scale for assessing acute postoperative pain in cattle is a valid, reliable and responsive instrument with excellent internal consistency and discriminatory ability. The cut-off point for rescue analgesia provides an additional tool for guiding analgesic therapy.

  10. Optimal Least-Squares Unidimensional Scaling: Improved Branch-and-Bound Procedures and Comparison to Dynamic Programming

    ERIC Educational Resources Information Center

    Brusco, Michael J.; Stahl, Stephanie

    2005-01-01

    There are two well-known methods for obtaining a guaranteed globally optimal solution to the problem of least-squares unidimensional scaling of a symmetric dissimilarity matrix: (a) dynamic programming, and (b) branch-and-bound. Dynamic programming is generally more efficient than branch-and-bound, but the former is limited to matrices with…

  11. The Effect of Fitting a Unidimensional IRT Model to Multidimensional Data in Content-Balanced Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Song, Tian

    2010-01-01

    This study investigates the effect of fitting a unidimensional IRT model to multidimensional data in content-balanced computerized adaptive testing (CAT). Unconstrained CAT with the maximum information item selection method is chosen as the baseline, and the performances of three content balancing procedures, the constrained CAT (CCAT), the…

  12. The Unidimensional Relationship Closeness Scale (URCS): Reliability and Validity Evidence for a New Measure of Relationship Closeness

    ERIC Educational Resources Information Center

    Dibble, Jayson L.; Levine, Timothy R.; Park, Hee Sun

    2012-01-01

    A fundamental dimension along which all social and personal relationships vary is closeness. The Unidimensional Relationship Closeness Scale (URCS) is a 12-item self-report scale measuring the closeness of social and personal relationships. The reliability and validity of the URCS were assessed with college dating couples (N = 192), female friends…

  13. Optimal Least-Squares Unidimensional Scaling: Improved Branch-and-Bound Procedures and Comparison to Dynamic Programming

    ERIC Educational Resources Information Center

    Brusco, Michael J.; Stahl, Stephanie

    2005-01-01

    There are two well-known methods for obtaining a guaranteed globally optimal solution to the problem of least-squares unidimensional scaling of a symmetric dissimilarity matrix: (a) dynamic programming, and (b) branch-and-bound. Dynamic programming is generally more efficient than branch-and-bound, but the former is limited to matrices with…

  14. Implicit-Explicit Formulations of a Three-Dimensional Nonhydrostatic Unified Model of the Atmosphere (NUMA)

    DTIC Science & Technology

    2013-01-01

    unification across various metrics. NUMA is unified in terms of spatial discretization methods and can use high-order continuous and discontinuous Galerkin ...dominate the solution error because we tend to use much higher order in space (e.g., 4th through 8th order) in the continuous/ discontinuous Galerkin ...tions, 52 (2006), pp. 1325–1342. [12] F. X. Giraldo and M. Restelli, A study of spectral element and discontinuous Galerkin methods for the Navier

  15. Current and Future Development of a Non-hydrostatic Unified Atmospheric Model (NUMA)

    DTIC Science & Technology

    2010-09-09

    Based on Spectral Elements and Discontinuous Galerkin methods –  Tested with simple moist physics (Kessler Physics) •  2010: 3D Mesoscale Atmospheric...Model (NUMA) –  Nonhydrostatic Equations –  Based on Spectral Element and Discontinuous Galerkin methods –  Tested as Limited-Area model (NRBCs...following capabilities: 1.  Highly scalable on current and future computer architectures (exascale computing and beyond and GPUs ) 2.  Flexibility

  16. Development of the Nonhydrostatic Unified Model of the Atmosphere (NUMA): Limited-Area Mode (Preprint)

    DTIC Science & Technology

    2011-04-14

    Applied Mathematics, Naval Postgraduate School , Monterey, CA Abstract This paper describes a Nonhydrostatic Unified Model of the Atmosphere (NUMA) based on...TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Naval Postgraduate School ,Department of Applied Mathematics...integrators and/or “ soundproof ” equation sets to confront the fast acoustic and gravity waves present in non-hydrostatic models, and 4) developing scalable

  17. The assessment of commitment: advantages of a unidimensional, target-free approach.

    PubMed

    Klein, Howard J; Cooper, Joseph T; Molloy, Janice C; Swanson, Jacqueline A

    2014-03-01

    This study presents a new approach to assessing commitment reflecting the Klein, Molloy, and Brinsfield (2012) reconceptualization. Klein et al. recast the construct to address issues hindering commitment scholarship, but their claims cannot be tested with existing measures. This paper presents a 4-item measure consistent with the Klein et al. conceptual definition, a measure intended to be unidimensional and applicable across all workplace targets. Our purpose is to present the development of and provide initial validity evidence for this new commitment measure and to compare it to existing alternative measures. Hypotheses around these objectives were tested with data gathered across 5 samples yielding 2,487 participants representing a wide range of jobs, organizations, and industries. Each sample examined a unique set of variables and targets that together provide a comprehensive test of this new measure relative to 8 different targets, several constructs within the nomological network, and 4 prior commitment measures. Results support our hypotheses regarding (a) the measure's properties and structure, (b) convergence and divergence with prior measures of commitment and other constructs in the nomological network, and (c) advantages over prior measures. These findings support the validity of this new approach to assessing commitment, laying the foundation for future research to address critiques of the commitment construct; better examine the multiple commitments individuals simultaneously hold; and bring consistency, synergy, and integration to commitment scholarship across workplace targets. The conceptual, methodological, and practical benefits of the measure are discussed, along with study limitations and future research opportunities.

  18. Creating Unidimensional Global Measures of Physician Practice Quality Based on Health Insurance Claims Data.

    PubMed

    Martsolf, Grant R; Carle, Adam C; Scanlon, Dennis P

    2017-06-01

    To explore the extent to which commonly used claims-based process quality indicators can be used to create an internally valid global composite measure of physician practice quality. Health insurance claims data (October 2007-May 2010) from 134 physician practices in Seattle, WA. We use confirmatory and exploratory factor analysis to develop theory- and empirically driven internally valid composite measures based on 19 quality indicators. Health insurance claims data from nine insurance companies and self-funded employers were collected and aggregated by third-party organization. Our results did not support a single global measure using the entire set of quality indicators. We did identify an acceptable multidimensional model (RMSEA = 0.059; CFI = 0.934; TLI = 0.910). The four dimensions in our data were diabetes, depression, preventive care, and generic drug prescribing. Our study demonstrates that commonly used process indicators can be used to create a small set of useful composite measures. However, the lack of an internally valid single unidimensional global measure has important implications for policy approaches meant to improve quality by rewarding "high-quality physicians." © Health Research and Educational Trust.

  19. Rasch analysis suggested three unidimensional domains for Affiliate Stigma Scale: additional psychometric evaluation.

    PubMed

    Chang, Chih-Cheng; Su, Jian-An; Tsai, Ching-Shu; Yen, Cheng-Fang; Liu, Jiun-Horng; Lin, Chung-Ying

    2015-06-01

    To examine the psychometrics of the Affiliate Stigma Scale using rigorous psychometric analysis: classical test theory (CTT) (traditional) and Rasch analysis (modern). Differential item functioning (DIF) items were also tested using Rasch analysis. Caregivers of relatives with mental illness (n = 453; mean age: 53.29 ± 13.50 years) were recruited from southern Taiwan. Each participant filled out four questionnaires: Affiliate Stigma Scale, Rosenberg Self-Esteem Scale, Beck Anxiety Inventory, and one background information sheet. CTT analyses showed that the Affiliate Stigma Scale had satisfactory internal consistency (α = 0.85-0.94) and concurrent validity (Rosenberg Self-Esteem Scale: r = -0.52 to -0.46; Beck Anxiety Inventory: r = 0.27-0.34). Rasch analyses supported the unidimensionality of three domains in the Affiliate Stigma Scale and indicated four DIF items (affect domain: 1; cognitive domain: 3) across gender. Our findings, based on rigorous statistical analysis, verified the psychometrics of the Affiliate Stigma Scale and reported its DIF items. We conclude that the three domains of the Affiliate Stigma Scale can be separately used and are suitable for measuring the affiliate stigma of caregivers of relatives with mental illness. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Epitope mapping and direct visualization of the parallel, in-register arrangement of the double-stranded coiled-coil in the NuMA protein.

    PubMed Central

    Harborth, J; Weber, K; Osborn, M

    1995-01-01

    NuMA, a 238 kDa protein present in the nucleus during interphase, translocates to the spindle poles in mitosis. NuMA plays an essential role in mitosis, since microinjection of the NuMA SPN-3 monoclonal antibody causes mitotic arrest and micronuclei formation. We have mapped the approximate position of the epitopes of six monoclonal NuMA antibodies using recombinant NuMA fragments. The SPN-3 epitope has been located to residues 255-267 at the C-terminus of the first helical subdomain of the central rod domain and several residues crucial for antibody binding have been identified. To gain insight into the ultrastructure of NuMA, several defined fragments, as well as the full-length recombinant protein, were expressed in Escherichia coli and purified to homogeneity. They were then characterized by chemical cross-linking, circular dichroism spectra and electron microscopy. The results directly reveal the tripartate structure of NuMA. A long central rod domain is flanked by globular end domains. The rod is 207 nm long and is at least 90% alpha-helical. It reflects a double-stranded coiled-coil with the alpha-helices arranged parallel and in register. The NuMA protein thus forms the longest coiled-coil currently known. Our analyses reveal no indication that recombinant NuMA assembles into filaments or other higher order structures. Images PMID:7781599

  1. Inequality in cataract blindness and services: moving beyond unidimensional analyses of social position.

    PubMed

    Ramke, Jacqueline; Zwi, Anthony B; Lee, Arier C; Blignault, Ilse; Gilbert, Clare E

    2017-04-01

    Inequalities in cataract blindness are well known, but data are rarely disaggregated to explore the combined effects of a range of axes describing social disadvantage. We examined inequalities in cataract blindness and services at the intersection of three social axes. Three dichotomous social variables (sex (male/female); place of residence (urban/rural); literacy (literate/illiterate)) from cross-sectional national blindness surveys in Pakistan (2001-2004; n=16 507) and Nigeria (2005-2007; n=13 591) were used to construct eight subgroups, with disadvantaged subgroups selected a priori (ie, women, rural dwellers, illiterate). In each data set, the social distribution of cataract blindness, cataract surgical coverage (CSC) and effective cataract surgical coverage (eCSC) were examined. Inequalities were assessed comparing the best-off and worst-off subgroups using rate differences and rate ratios (RRs). Logistic regression was used to assess cumulative effects of multiple disadvantage. Disadvantaged subgroups experienced higher prevalence of cataract blindness, lower CSC and lower eCSC in both countries. A social gradient was present for CSC and eCSC, with coverage increasing as social position improved. Relative inequality in eCSC was approximately twice as high as CSC (Pakistan: eCSC RR 2.7 vs CSC RR 1.3; Nigeria: eCSC RR 8.7 vs CSC RR 4.1). Cumulative disadvantage was observed for all outcomes, deteriorating further with each additional axis along which disadvantage was experienced. Each outcome tended to be worse with the addition of each layer of social disadvantage. Illiterate, rural women fared worst in both settings. Moving beyond unidimensional analyses of social position identified subgroups in most need; this permits a more nuanced response to addressing the inequitable distribution of cataract blindness. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  2. Scale construction utilising the Rasch unidimensional measurement model: A measurement of adolescent attitudes towards abortion.

    PubMed

    Hendriks, Jacqueline; Fyfe, Sue; Styles, Irene; Skinner, S Rachel; Merriman, Gareth

    2012-01-01

    Measurement scales seeking to quantify latent traits like attitudes, are often developed using traditional psychometric approaches. Application of the Rasch unidimensional measurement model may complement or replace these techniques, as the model can be used to construct scales and check their psychometric properties. If data fit the model, then a scale with invariant measurement properties, including interval-level scores, will have been developed. This paper highlights the unique properties of the Rasch model. Items developed to measure adolescent attitudes towards abortion are used to exemplify the process. Ten attitude and intention items relating to abortion were answered by 406 adolescents aged 12 to 19 years, as part of the "Teen Relationships Study". The sampling framework captured a range of sexual and pregnancy experiences. Items were assessed for fit to the Rasch model including checks for Differential Item Functioning (DIF) by gender, sexual experience or pregnancy experience. Rasch analysis of the original dataset initially demonstrated that some items did not fit the model. Rescoring of one item (B5) and removal of another (L31) resulted in fit, as shown by a non-significant item-trait interaction total chi-square and a mean log residual fit statistic for items of -0.05 (SD=1.43). No DIF existed for the revised scale. However, items did not distinguish as well amongst persons with the most intense attitudes as they did for other persons. A person separation index of 0.82 indicated good reliability. Application of the Rasch model produced a valid and reliable scale measuring adolescent attitudes towards abortion, with stable measurement properties. The Rasch process provided an extensive range of diagnostic information concerning item and person fit, enabling changes to be made to scale items. This example shows the value of the Rasch model in developing scales for both social science and health disciplines.

  3. Unidimensional Measurement May Evaluate Target Lymph Nodal Response After Induction Chemotherapy for Nasopharyngeal Carcinoma

    PubMed Central

    Chen, Chuanben; Zhang, Mingwei; Xu, Yuanji; Yue, Qiuyuan; Bai, Penggang; Zhou, Lin; Xiao, Youping; Zheng, Dechun; Lin, Kongqi; Qiu, Sufang; Chen, Yunbin; Pan, Jianji

    2016-01-01

    Abstract The aim of the study was to evaluate whether short axis and long axis on axial and coronal magnetic resonance imaging planes would reflect the tumor burden or alteration in size after induction chemotherapy in nasopharyngeal carcinoma. Patients with pathologically confirmed nasopharyngeal carcinoma (n = 37) with at least 1 positive cervical lymph node (axial short axis ≥15 mm) were consecutively enrolled in this prospective study. Lymph nodal measurements were performed along its short axis and long axis in both axial and coronal magnetic resonance imaging planes at diagnosis and after 2 cycles of induction chemotherapy. In addition, lymph nodal volumes were automatically calculated in 3D treatment-planning system, which were used as reference standard. Student's t test or nonparametric Mann–Whitney U test was used to compare the continuous quantitative variables. Meanwhile, the κ statistic and McNemar's test were used to evaluate the degree of agreement and discordance in response categorization among different measurements. Axial short axis was significantly associated with volumes at diagnosis (P < 0.001). A good agreement (κ=0.583) was found between axial short axis and volumetric criteria. However, the inconsistent lymph nodal shrinkage in 4 directions was observed. Axial short-axis shrinking was more rapid than the other 3 parameters. Interestingly, when utilizing the alternative planes for unidimensional measurements to assess tumor response, coronal short-axis showed the best concordance (κ=0.792) to the volumes. Axial short axis may effectively reflect tumor burden or change in tumor size in the assessment of target lymph nodal response after induction chemotherapy for nasopharyngeal carcinoma. However, it should be noted that axial short axis may amplify the therapeutic response. In addition, the role of coronal short axis in the assessment of tumor response needs further evaluation. PMID:26945354

  4. Developments in REDES: The Rocket Engine Design Expert System

    NASA Technical Reports Server (NTRS)

    Davidian, Kenneth O.

    1990-01-01

    The Rocket Engine Design Expert System (REDES) was developed at NASA-Lewis to collect, automate, and perpetuate the existing expertise of performing a comprehensive rocket engine analysis and design. Currently, REDES uses the rigorous JANNAF methodology to analyze the performance of the thrust chamber and perform computational studies of liquid rocket engine problems. The following computer codes were included in REDES: a gas properties program named GASP; a nozzle design program named RAO; a regenerative cooling channel performance evaluation code named RTE; and the JANNAF standard liquid rocket engine performance prediction code TDK (including performance evaluation modules ODE, ODK, TDE, TDK, and BLM). Computational analyses are being conducted by REDES to provide solutions to liquid rocket engine thrust chamber problems. REDES was built in the Knowledge Engineering Environment (KEE) expert system shell and runs on a Sun 4/110 computer.

  5. Developments in REDES: The rocket engine design expert system

    NASA Technical Reports Server (NTRS)

    Davidian, Kenneth O.

    1990-01-01

    The Rocket Engine Design Expert System (REDES) is being developed at the NASA-Lewis to collect, automate, and perpetuate the existing expertise of performing a comprehensive rocket engine analysis and design. Currently, REDES uses the rigorous JANNAF methodology to analyze the performance of the thrust chamber and perform computational studies of liquid rocket engine problems. The following computer codes were included in REDES: a gas properties program named GASP, a nozzle design program named RAO, a regenerative cooling channel performance evaluation code named RTE, and the JANNAF standard liquid rocket engine performance prediction code TDK (including performance evaluation modules ODE, ODK, TDE, TDK, and BLM). Computational analyses are being conducted by REDES to provide solutions to liquid rocket engine thrust chamber problems. REDES is built in the Knowledge Engineering Environment (KEE) expert system shell and runs on a Sun 4/110 computer.

  6. Novel t(5;11)(q32;q13.4) with NUMA1-PDGFRB fusion in a myeloid neoplasm with eosinophilia with response to imatinib mesylate.

    PubMed

    Zou, Ying S; Hoppman, Nicole L; Singh, Zeba N; Sawhney, Sameer; Kotiah, Sandy D; Baer, Maria R

    2017-04-01

    We report a NUMA1-PDGFRB fusion in a myeloproliferative neoplasm with eosinophilia in a 61-year old man, with response to imatinib mesylate therapy. A t(5;11) chromosome translocation involving bands 5q32 and 11q13.4 was identified by metaphase chromosome analysis, and rearrangement of the platelet-derived growth factor receptor beta (PDGFRB) gene on 5q32 was demonstrated by FISH using a PDGFRB break-apart probe set. Bacterial artificial chromosome (BAC) FISH mapping of the PDGFRB fusion partner gene narrowed the breakpoint at 11q13.4 to a 150 kb genomic region containing three genes, including NUMA1. Mate pair sequencing analysis demonstrated NUMA1-PDGFRB fusion. The fusion protein includes coiled-coil domains of nuclear mitotic apparatus protein 1 (NuMA1, involved in protein homodimerization and heteroassociation) and tyrosine kinase domains of PDGFRB. Diverse rearrangements involving the PDGFRB gene have been identified in myeloid and lymphoid neoplasms with eosinophilia, but rearrangement of the nuclear mitotic apparatus protein 1 (NUMA1) gene has previously been reported in a human malignancy in only one instance, a NUMA1-RARA fusion caused by a t(11;17) translocation in a patient with acute promyelocytic leukemia. The NUMA1-PDGFRB fusion is the second instance of rearrangement of NUMA1, encoding an element of the mitotic apparatus, in human cancer. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. The use of the bi-factor model to test the uni-dimensionality of a battery of reasoning tests.

    PubMed

    Primi, Ricardo; Rocha da Silva, Marjorie Cristina; Rodrigues, Priscila; Muniz, Monalisa; Almeida, Leandro S

    2013-02-01

    The Battery of Reasoning Tests 5 (BPR-5) aims to assess the reasoning ability of individuals, using sub-tests with different formats and contents that require basic processes of inductive and deductive reasoning for their resolution. The BPR has three sequential forms: BPR-5i (for children from first to fifth grade), BPR-5 - Form A (for children from sixth to eighth grade) and BPR-5 - form B (for high school and undergraduate students). The present study analysed 412 questionnaires concerning BPR-5i, 603 questionnaires concerning BPR-5 - Form A and 1748 questionnaires concerning BPR-5 - Form B. The main goal was to test the uni-dimensionality of the battery and its tests in relation to items using the bi-factor model. Results suggest that the g factor loadings (extracted by the uni-dimensional model) do not change when the data is adjusted for a more flexible multi-factor model (bi-factor model). A general reasoning factor underlying different contents items is supported.

  8. SRS-7: A Valid, Responsive, Linear, and Unidimensional Functional Outcome Measure for Operatively Treated Patients With AIS.

    PubMed

    Jain, Amit; Sponseller, Paul D; Negrini, Stefano; Newton, Peter O; Cahill, Patrick J; Bastrom, Tracey P; Marks, Michelle C

    2015-05-01

    Comparison of the Scoliosis Research Society-22 (SRS-22) questionnaire with a 7-item Rasch-derived questionnaire (SRS-7). To compare the construct and discriminant validity, internal consistency, responsiveness, and dimensionality of SRS-7 against SRS-22 in operatively treated children with adolescent idiopathic scoliosis. SRS-22 has not been shown to possess linearity or unidimensionality (internal validity). A multicenter database was queried for children with adolescent idiopathic scoliosis who underwent spinal fusion and answered all preoperative and 1-year postoperative SRS-22 questions. SRS-7 scores for the 685 patients were calculated from SRS-22 item responses. Traditional psychometric properties were assessed for both instruments (significance, P < 0.01). SRS-7 and SRS-22 scores correlated preoperatively and postoperatively (r = 0.78, P < 0.001, and r = 0.78, P < 0.001, respectively). Both instruments showed good discriminant validity in segregating 4 groups of patients with adolescent idiopathic scoliosis by curve magnitudes (F = 8.36, P < 0.001, and F = 8.38, P < 0.001, respectively). Pre- and postoperative SRS-7 and SRS-22 had internal consistency Cronbach α values of 0.64 and 0.67, and 0.85 and 0.85, respectively. With SRS-7, mean postsurgical improvement was 18.7 points (46.6-65.3, P < 0.001), with effect size measures of Cohen d = 1.57, Hedge g = 1.57, and r = 0.62. With SRS-22, mean improvement was 11.6 points (84.5-96.1, P < 0.01), with effect size measures of Cohen d = 1.25, Hedge g = 1.25, and r = 0.53. Iterative principal factor analysis of pre- and postoperative SRS-7 and SRS-22 showed the presence of 1 dominant latent factor (unidimensionality) and 4 latent factors (multidimensionality), respectively. SRS-7 shows good concurrent and discriminative validity, reasonable internal consistency, and excellent responsiveness. It has the advantages over SRS-22 of being short, unidimensional, and an interval scale. 4.

  9. Parallel calculations on shared memory, NUMA-based computers using MATLAB

    NASA Astrophysics Data System (ADS)

    Krotkiewski, Marcin; Dabrowski, Marcin

    2014-05-01

    Achieving satisfactory computational performance in numerical simulations on modern computer architectures can be a complex task. Multi-core design makes it necessary to parallelize the code. Efficient parallelization on NUMA (Non-Uniform Memory Access) shared memory architectures necessitates explicit placement of the data in the memory close to the CPU that uses it. In addition, using more than 8 CPUs (~100 cores) requires a cluster solution of interconnected nodes, which involves (expensive) communication between the processors. It takes significant effort to overcome these challenges even when programming in low-level languages, which give the programmer full control over data placement and work distribution. Instead, many modelers use high-level tools such as MATLAB, which severely limit the optimization/tuning options available. Nonetheless, the advantage of programming simplicity and a large available code base can tip the scale in favor of MATLAB. We investigate whether MATLAB can be used for efficient, parallel computations on modern shared memory architectures. A common approach to performance optimization of MATLAB programs is to identify a bottleneck and migrate the corresponding code block to a MEX file implemented in, e.g. C. Instead, we aim at achieving a scalable parallel performance of MATLABs core functionality. Some of the MATLABs internal functions (e.g., bsxfun, sort, BLAS3, operations on vectors) are multi-threaded. Achieving high parallel efficiency of those may potentially improve the performance of significant portion of MATLABs code base. Since we do not have MATLABs source code, our performance tuning relies on the tools provided by the operating system alone. Most importantly, we use custom memory allocation routines, thread to CPU binding, and memory page migration. The performance tests are carried out on multi-socket shared memory systems (2- and 4-way Intel-based computers), as well as a Distributed Shared Memory machine with 96 CPU

  10. Performance of the likelihood ratio difference (G2 Diff) test for detecting unidimensionality in applications of the multidimensional Rasch model.

    PubMed

    Harrell-Williams, Leigh; Wolfe, Edward W

    2014-01-01

    Previous research has investigated the influence of sample size, model misspecification, test length, ability distribution offset, and generating model on the likelihood ratio difference test in applications of item response models. This study extended that research to the evaluation of dimensionality using the multidimensional random coefficients multinomial logit model (MRCMLM). Logistic regression analysis of simulated data reveal that sample size and test length have a large effect on the capacity of the LR difference test to correctly identify unidimensionality, with shorter tests and smaller sample sizes leading to smaller Type I error rates. Higher levels of simulated misfit resulted in fewer incorrect decisions than data with no or little misfit. However, Type I error rates indicate that the likelihood ratio difference test is not suitable under any of the simulated conditions for evaluating dimensionality in applications of the MRCMLM.

  11. NMR characterisation of the minimal interacting regions of centrosomal proteins 4.1R and NuMA1: effect of phosphorylation

    PubMed Central

    2010-01-01

    Background Some functions of 4.1R in non-erythroid cells are directly related with its distinct sub-cellular localisation during cell cycle phases. During mitosis, 4.1R is implicated in cell cycle progression and spindle pole formation, and co-localizes with NuMA1. However, during interphase 4.1R is located in the nucleus and only partially co-localizes with NuMA1. Results We have characterized by NMR the structural features of the C-terminal domain of 4.1R and those of the minimal region (the last 64 residues) involved in the interaction with NuMA1. This subdomain behaves as an intrinsically unfolded protein containing a central region with helical tendency. The specific residues implicated in the interaction with NuMA1 have been mapped by NMR titrations and involve the N-terminal and central helical regions. The segment of NuMA1 that interacts with 4.1R is phosphorylated during mitosis. Interestingly, NMR data indicates that the phosphorylation of NuMA1 interacting peptide provokes a change in the interaction mechanism. In this case, the recognition occurs through the central helical region as well as through the C-terminal region of the subdomain meanwhile the N-terminal region do not interact. Conclusions These changes in the interaction derived from the phosphorylation state of NuMA1 suggest that phosphorylation can act as subtle mechanism of temporal and spatial regulation of the complex 4.1R-NuMA1 and therefore of the processes where both proteins play a role. PMID:20109190

  12. Is acculturation unidimensional or bidimensional? A head-to-head comparison in the prediction of personality, self-identity, and adjustment.

    PubMed

    Ryder, A G; Alden, L E; Paulhus, D L

    2000-07-01

    The unidimensional model of acculturation posits that heritage and mainstream culture identifications have a strong inverse relation, whereas the bidimensional model posits that the 2 identifications are independent. The authors compared these models in 3 samples of ethnic Chinese (ns = 164, 150, and 204), 1 sample of non-Chinese East Asians (n = 70), and one diverse group of acculturating individuals (n = 140). Although the unidimensional measure showed a coherent pattern of external correlates, the bidimensional measure revealed independent dimensions corresponding to heritage and mainstream culture identification. These dimensions displayed patterns of noninverse correlations with personality, self-identity, and psychosocial adjustment. The authors conclude that the bidimensional model is a more valid and useful operationalization of acculturation.

  13. Reciprocal Effects of Self-Concept and Performance From a Multidimensional Perspective: Beyond Seductive Pleasure and Unidimensional Perspectives.

    PubMed

    Marsh, Herbert W; Craven, Rhonda G

    2006-06-01

    We (Marsh & Craven, 1997) have claimed that academic self-concept and achievement are mutually reinforcing, each leading to gains in the other. Baumeister, Campbell, Krueger, and Vohs (2003) have claimed that self-esteem has no benefits beyond seductive pleasure and may even be detrimental to subsequent performance. Integrating these seemingly contradictory conclusions, we distinguish between (a) older, unidimensional perspectives that focus on global self-esteem and underpin the Baumeister et al. review and (b) more recent, multidimensional perspectives that focus on specific components of self-concept and are the basis of our claim. Supporting the construct validity of a multidimensional perspective, studies show that academic achievement is substantially related to academic self-concept, but nearly unrelated to self-esteem. Consistent with this distinction, research based on our reciprocal-effects model (REM) and a recent meta-analysis show that prior academic self-concept (as opposed to self-esteem) and achievement both have positive effects on subsequent self-concept and achievement. We provide an overview of new support for the generality of the REM for young children, cross-cultural research in non-Western countries, health (physical activity), and nonelite (gymnastics) and elite (international swimming championships) sport. We conclude that future reviews elucidating the significant implications of self-concept for theory, policy, and practice need to account for current research supporting the REM and a multidimensional perspective of self-concept.

  14. Lax-Wendroff and TVD finite volume methods for unidimensional thermomechanical numerical simulations of impacts on elastic-plastic solids

    NASA Astrophysics Data System (ADS)

    Heuzé, Thomas

    2017-10-01

    We present in this work two finite volume methods for the simulation of unidimensional impact problems, both for bars and plane waves, on elastic-plastic solid media within the small strain framework. First, an extension of Lax-Wendroff to elastic-plastic constitutive models with linear and nonlinear hardenings is presented. Second, a high order TVD method based on flux-difference splitting [1] and Superbee flux limiter [2] is coupled with an approximate elastic-plastic Riemann solver for nonlinear hardenings, and follows that of Fogarty [3] for linear ones. Thermomechanical coupling is accounted for through dissipation heating and thermal softening, and adiabatic conditions are assumed. This paper essentially focuses on one-dimensional problems since analytical solutions exist or can easily be developed. Accordingly, these two numerical methods are compared to analytical solutions and to the explicit finite element method on test cases involving discontinuous and continuous solutions. This allows to study in more details their respective performance during the loading, unloading and reloading stages. Particular emphasis is also paid to the accuracy of the computed plastic strains, some differences being found according to the numerical method used. Lax-Wendoff two-dimensional discretization of a one-dimensional problem is also appended at the end to demonstrate the extensibility of such numerical scheme to multidimensional problems.

  15. O Universo das Sociedades Numa Perspectiva Relativa: Exercícios de Etnoastronomia

    NASA Astrophysics Data System (ADS)

    Fares, Érika Akel; Pessoa Martins, Karla; Maciel Araujo, Lidiane; Sauma Filho, Michel

    2004-12-01

    This work developed at the Planetarium of Pará employing workshops designed for visitor schools (public, private, specials groups), promotes the popularization of the Ethnoastronomy with the aim of diffusing values based on a cultural diversity tolerance and the need of harmonic interplay between people and environment. Using stories and debates, the relationship between humans and the Cosmos is traced from antiquity until today, with the help of slides as a didactic resource. Thus, many conceptions about the origin of the Universe are shown; as well as some constellations created along the History, ending with the present scientific manner of know and explain the World. We then demonstrate the links between space, time and culture with the Cosmos vision. The need to think the World within a plural context to create respect for other different persons is emphasized. Este trabalho, desenvolvido no Planetário do Pará através de oficinas com escolas visitantes (públicas, privadas e grupos especiais), promove a popularização da Etnoastronomia, com o objetivo de difundir valores pautados na tolerância à diversidade cultural e na necessidade da convivência harmônica entre o ser humano e o meio ambiente. Através da contação de histórias e promoção de debate, é tratada a relação dos humanos com o céu desde a antiguidade até os dias atuais, tendo como apoio didático o uso de slides. Assim, são mostradas diversas concepções de origem do Universo; algumas constelações criadas no decorrer da História; e a atual forma científica de conhecer e explicar o mundo. Demonstrando-se, então, a interligação entre espaço, tempo e cultura com a visão do Cosmo. Enfatiza-se a necessidade de se pensar o mundo numa perspectiva relativa ou plural, de forma a propiciar o respeito ao ser diferente.

  16. Rasch analysis for assessing unidimensionality and identifying measurement biases of malignancy scores in oncology. The example of the Weiss histopathological system for the diagnosis of adrenocortical cancer.

    PubMed

    Coste, Joël; Tissier, Frédérique; Pouchot, Jacques; Ecosse, Emmanuel; Rouquette, Alexandra; Bertagna, Xavier; Libé, Rossella; Viallon, Vivian

    2014-04-01

    Many malignancy scores have been developed without comprehensive statistical or measurement validation, and in particular without verification of the necessary property of unidimensionality. Here, we used Rasch analysis to assess unidimensionality and identify measurement biases of malignancy scores. The Weiss histopathological system (WHS), summing nine items of histopathological alteration, was used to evaluate 247 adrenocortical tumors. Rasch model analysis was implemented and compared to classical factor analytic methods to investigate the validity of item-score summation for both the original and modified WHS, to assess differential functioning of the WHS items across various factors related to patient and tumors, and to identify items or subtypes of tumors that could be considered for removal or exclusion from the WHS with the aims of improving measurement and relieving the burden on pathologists. The WHS does not meet the necessary property of unidimensionality and is severely affected by differential item functioning in relation to size and weight of the tumor. Moreover, items are not well distributed along the spectrum of malignancy, most being located in the upper part and several at the same place. The WHS in its present form should be applied only to small or moderate size tumors, and better scoring systems could be developed by using more appropriately distributed items. Rasch analysis is a powerful method for developing, evaluating, refining and simplifying malignancy scores. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Achieving High Performance With TCP Over 40 GbE on NUMA Architectures for CMS Data Acquisition

    SciTech Connect

    Bawej, Tomasz; et al.

    2014-01-01

    TCP and the socket abstraction have barely changed over the last two decades, but at the network layer there has been a giant leap from a few megabits to 100 gigabits in bandwidth. At the same time, CPU architectures have evolved into the multicore era and applications are expected to make full use of all available resources. Applications in the data acquisition domain based on the standard socket library running in a Non-Uniform Memory Access (NUMA) architecture are unable to reach full efficiency and scalability without the software being adequately aware about the IRQ (Interrupt Request), CPU and memory affinities. During the first long shutdown of LHC, the CMS DAQ system is going to be upgraded for operation from 2015 onwards and a new software component has been designed and developed in the CMS online framework for transferring data with sockets. This software attempts to wrap the low-level socket library to ease higher-level programming with an API based on an asynchronous event driven model similar to the DAT uDAPL API. It is an event-based application with NUMA optimizations, that allows for a high throughput of data across a large distributed system. This paper describes the architecture, the technologies involved and the performance measurements of the software in the context of the CMS distributed event building.

  18. LAMTOR1-PRKCD and NUMA1-SFMBT1 fusion genes identified by RNA sequencing in aneurysmal benign fibrous histiocytoma with t(3;11)(p21;q13).

    PubMed

    Panagopoulos, Ioannis; Gorunova, Ludmila; Bjerkehagen, Bodil; Lobmaier, Ingvild; Heim, Sverre

    2015-11-01

    RNA sequencing of an aneurysmal benign fibrous histiocytoma with the karyotype 46,XY,t(3;11)(p21;q13),del(6)(p23)[17]/46,XY[2] showed that the t(3;11) generated two fusion genes: LAMTOR1-PRKCD and NUMA1-SFMBT1. RT-PCR together with Sanger sequencing verified the presence of fusion transcripts from both fusion genes. In the LAMTOR1-PRKCD fusion, the part of the PRKCD gene coding for the catalytic domain of the serine/threonine kinase is under control of the LAMTOR1 promoter. In the NUMA1-SFMBT1 fusion, the part of the SFMBT1 gene coding for two of four malignant brain tumor domains and the sterile alpha motif domain is controlled by the NUMA1 promoter. The data support a neoplastic genesis of aneurysmal benign fibrous histiocytoma and indicate a pathogenetic role for LAMTOR1-PRKCD and NUMA1-SFMBT1. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Chronic Pain Assessments in Children and Adolescents: A Systematic Literature Review of the Selection, Administration, Interpretation, and Reporting of Unidimensional Pain Intensity Scales

    PubMed Central

    Lee, Rebecca Rachael; Rashid, Amir; Ghio, Daniela; Thomson, Wendy

    2017-01-01

    Background Advances in pain assessment approaches now indicate which measures should be used to capture chronic pain experiences in children and adolescents. However, there is little guidance on how these tools should best be administered and reported, such as which time frames to use or how pain scores are categorised as mild, moderate, or severe. Objective To synthesise current evidence on unidimensional, single-item pain intensity scale selection, administration, interpretation, and reporting. Methods Databases were searched (inception: 18 January 2016) for studies in which unidimensional pain intensity assessments were used with children and adolescents with chronic pain. Ten quality criteria were developed by modifying existing recommendations to evaluate the quality of administration of pain scales most commonly used with children. Results Forty-six studies met the inclusion criteria. The highest score achieved was 7 out of a possible 10 (median: 5; IQR: 4–6). Usage of scales varied markedly in administrator/completer, highest anchors, number of successive assessments, and time referent periods used. Conclusions Findings suggest these scales are selected, administered, and interpreted inconsistently, even in studies of the same type. Furthermore, methods of administration are rarely reported or justified making it impossible to compare findings across studies. This article concludes by recommending criteria for the future reporting of paediatric chronic pain assessments in studies. PMID:28912638

  20. Unidimensionality of life satisfaction and its relation to social desirability: a confirmatory study of a short form of the Life Satisfaction Scale.

    PubMed

    Laicardi, C; Baldassarri, F; Artistico, D

    2001-02-01

    This study investigated construct validity of a short version of the Life Satisfaction in the Elderly Scale developed from an exploratory factor analysis in 1990 of the original version of Salamon and Conte's Life Satisfaction scale. First, a confirmatory factor analysis (maximum likelihood method) was conducted on 149 adult and elderly Italians to assess whether the latent variable of the Life Satisfaction Short Form scale was adequately represented by one factor. Analysis showed a good fit for the proposed unidimensional model, the items achieved good internal consistency on the scale, and no age differences arose in the score for the Life Satisfaction factor. Second, the correlations between the items measuring Life Satisfaction and the Eysenck 1985 Lie scale indicated that the items on the Life Satisfaction Short Form are largely independent of social desirability for younger and older adults.

  1. Regional Emissions Data Base and Evaluation System (REDES): Technical and system documentation of Version 2. 0

    SciTech Connect

    Rausch, J.V.; Boyd, G.A.

    1990-11-01

    The US Department of Energy (DOE) Innovative Clean Coal Technology (ICCT) program has solicited proposals from the private sector to demonstrate innovative technologies that allow the clean use of coal as an energy source. To aid in evaluating the potential of these proposed technologies to reduce environmental residuals, DOE and ICCT Source Evaluation Board asked Argonne National Laboratory to develop a series of data bases and a personal-computer-based model. Argonne created version 1.0 of the Regional Emissions Data Base and Evaluation System (REDES) in 1988. Version 1.0 was revised, and Version 2.0 was released in 1989. Version 2.0 of REDES is available to the public through the National Energy Software Center (telephone 708-972-7250). In 1988, Argonne National Laboratory published Regional Emissions Data Base and Evaluation System (REDES), report ANL/EES-TM-351, to document Version 1.0 of the REDES data bases and the computer model. In 1990, Argonne prepared this report to describe the changes and improvements that were made to Version 1.0 of REDES to create Version 2.0. Together with ANL/EES/TM-351, this report provides the user with a complete description of REDES, which is designed to forecast the change in emissions that could result from using a particular clean coal technology. 29 figs., 6 tabs.

  2. Validation of the Italian version of the UNESP-Botucatu unidimensional composite pain scale for the assessment of postoperative pain in cattle.

    PubMed

    Della Rocca, Giorgia; Brondani, Juliana Tabarelli; de Oliveira, Flávia Augusta; Crociati, Martina; Sylla, Lakamy; Elad Ngonput, Agnes; Di Salvo, Alessandra; Luna, Stelio Pacca Loureiro

    2017-03-06

    The aim of this study was to validate the Italian version of the UNESP-Botucatu Unidimensional Composite Pain Scale (UCPS-IV) for assessing postoperative pain in cattle. Video analysis and psychometric testing. A total of 40 Nellore cattle, age 2-3 years, weighing 365±51 kg. An English version of the scale was translated to Italian and back translated to English to ensure semantic equivalence. A total of four Italian observers and the researcher who developed the original scale (considered as the gold standard) analysed videos of 40 cattle previously subjected to orchiectomy (recorded for each cattle at four predetermined timepoints during the perioperative period) unaware of the videos' timepoint. They assigned a pain score [ranging from no pain (0) to severe pain (10)] using the Italian version of the scale and verified the need for analgesic treatment for each animal. The obtained scores were subjected to psychometric validity, responsiveness and reliability tests. The factor analysis of the scale resulted in a one-factor solution. Significant changes in pain scores in response to surgery and analgesics confirmed not only the content and construct validity, but also responsiveness. The agreement between the researcher who developed the original scale and the blinded observers and the correlation between the pain scores determined by the scale and those determined by three classical unidimensional pain scales confirmed criterion and concurrent validity. Internal consistency of the scale was excellent. Inter- and intrarater reliability ranged from moderate to good and from moderate to very good for all scale items, respectively, supporting reproducibility and stability. The cut-off point for rescue analgesia calculated by the receiver operating characteristic curve was > 3. The results confirm that the UNESP-Botucatu UCPS-IV appears to be a valid and reliable tool for the assessment of postorchiectomy pain in the bovine species. The determination of a cut

  3. Uni-dimensional double development HPTLC-densitometry method for simultaneous analysis of mangiferin and lupeol content in mango (Mangifera indica) pulp and peel during storage.

    PubMed

    Jyotshna; Srivastava, Pooja; Killadi, Bharti; Shanker, Karuna

    2015-06-01

    Mango (Mangifera indica) fruit is one of the important commercial fruit crops of India. Similar to other tropical fruits it is also highly perishable in nature. During storage/ripening, changes in its physico-chemical quality parameters viz. firmness, titrable acidity, total soluble solid content (TSSC), carotenoids content, and other biochemicals are inevitable. A uni-dimensional double-development high-performance thin-layer chromatography (UDDD-HPTLC) method was developed for the real-time monitoring of mangiferin and lupeol in mango pulp and peel during storage. The quantitative determination of both compounds of different classes was achieved by densitometric HPTLC method. Silica gel 60F254 HPTLC plates and two solvent systems viz. toluene/EtOAC/MeOH and EtOAC/MeOH, respectively were used for optimum separation and selective evaluation. Densitometric quantitation of mangiferin was performed at 390nm, while lupeol at 610nm after post chromatographic derivatization. Validated method was used to real-time monitoring of mangiferin and lupeol content during storage in four Indian cultivars, e.g. Bombay green (Bgreen), Dashehari, Langra, and Chausa. Significant correlations (p<0.05) between of acidity and TSSC with mangiferin and lupeol in pulp and peel during storage were also observed.

  4. Regional emissions data base and evaluation system (REDES): Volume 1, Methodology and user guide

    SciTech Connect

    Boyd, G.A.; VanGroningen, C.; Abel, L.

    1988-06-01

    This report describes an IBM personal-computer (PC) based system designed to aid in the evaluation of proposals to develop and demonstrate new technologies making clean use of coal. It forecasts the emissions that could result from the commercial introduction of a proposed clean coal technology, based on a user-defined market. These emission evaluations for each proposed technology can be saved for future analysis and comparison. The REDES program gives the user a systematic process for entering the characteristics of a particular clean coal technology; it then evaluates and reports on the potential impact that the introduction and commercialization of this proposed technology would have on the environment. In a sense, REDES is like a black box. It will produce evaluations based on any technology characteristics that it receives as input. To help the user of REDES determine the performance that might be expected from these emerging technologies, a set of generic technology characterizations are provided in the data base as a guide (see Vol.3). REDES is written as a run-time module in GURU, an expert system and relational data-base package from Micro Database Systems, Inc. (MDBS) for the IBM PC and compatibles. REDES cannot be executed without the run-time GURU program. This program must be obtained directly from MDBS; it is not available from Argonne National Laboratory (ANL). 15 figs., 5 tabs.

  5. Redes En Acción. Increasing Hispanic participation in cancer research, training, and awareness.

    PubMed

    Ramirez, Amelie G; Talavera, Gregory A; Marti, Jose; Penedo, Frank J; Medrano, Martha A; Giachello, Aida L; Pérez-Stable, Eliseo J

    2006-10-15

    Hispanics are affected by many health care disparities. The National Cancer Institute (NCI), through its Special Populations Branch, is supporting networking and capacity-building activities designed to increase Hispanic participation and leadership in cancer research. Redes En Acción established a national network of cancer research centers, community-based organizations, and federal partners to facilitate opportunities for junior Hispanic scientists to participate in training and research projects on cancer control. Since 2000, Redes En Acción has established a network of more than 1800 Hispanic leaders involved in cancer research and education. The project has sustained 131 training positions and submitted 29 pilot projects to NCI for review, with 16 awards for a total of $800,000, plus an additional $8.8 million in competing grant funding based on pilot study results to date. Independent research has leveraged an additional $32 million in non-Redes funding, and together the national and regional network sites have participated in more than 1400 community and professional awareness events. In addition, the program conducted extensive national survey research that provided the basis for the Redes En Acción Latino Cancer Report, a national agenda on Hispanic cancer issues. Redes En Acción has increased participation in cancer control research, training, and awareness among Hispanic scientists and within Hispanic communities. Cancer 2006. (c) 2006 American Cancer Society.

  6. High-content image informatics of the structural nuclear protein NuMA parses trajectories for stem/progenitor cell lineages and oncogenic transformation.

    PubMed

    Vega, Sebastián L; Liu, Er; Arvind, Varun; Bushman, Jared; Sung, Hak-Joon; Becker, Matthew L; Lelièvre, Sophie; Kohn, Joachim; Vidi, Pierre-Alexandre; Moghe, Prabhas V

    2017-02-01

    Stem and progenitor cells that exhibit significant regenerative potential and critical roles in cancer initiation and progression remain difficult to characterize. Cell fates are determined by reciprocal signaling between the cell microenvironment and the nucleus; hence parameters derived from nuclear remodeling are ideal candidates for stem/progenitor cell characterization. Here we applied high-content, single cell analysis of nuclear shape and organization to examine stem and progenitor cells destined to distinct differentiation endpoints, yet undistinguishable by conventional methods. Nuclear descriptors defined through image informatics classified mesenchymal stem cells poised to either adipogenic or osteogenic differentiation, and oligodendrocyte precursors isolated from different regions of the brain and destined to distinct astrocyte subtypes. Nuclear descriptors also revealed early changes in stem cells after chemical oncogenesis, allowing the identification of a class of cancer-mitigating biomaterials. To capture the metrology of nuclear changes, we developed a simple and quantitative "imaging-derived" parsing index, which reflects the dynamic evolution of the high-dimensional space of nuclear organizational features. A comparative analysis of parsing outcomes via either nuclear shape or textural metrics of the nuclear structural protein NuMA indicates the nuclear shape alone is a weak phenotypic predictor. In contrast, variations in the NuMA organization parsed emergent cell phenotypes and discerned emergent stages of stem cell transformation, supporting a prognosticating role for this protein in the outcomes of nuclear functions.

  7. RedeR: R/Bioconductor package for representing modular structures, nested networks and multiple levels of hierarchical associations

    PubMed Central

    2012-01-01

    Visualization and analysis of molecular networks are both central to systems biology. However, there still exists a large technological gap between them, especially when assessing multiple network levels or hierarchies. Here we present RedeR, an R/Bioconductor package combined with a Java core engine for representing modular networks. The functionality of RedeR is demonstrated in two different scenarios: hierarchical and modular organization in gene co-expression networks and nested structures in time-course gene expression subnetworks. Our results demonstrate RedeR as a new framework to deal with the multiple network levels that are inherent to complex biological systems. RedeR is available from http://bioconductor.org/packages/release/bioc/html/RedeR.html. PMID:22531049

  8. Exploring intra- and inter-reader variability in uni-dimensional, bi-dimensional, and volumetric measurements of solid tumors on CT scans reconstructed at different slice intervals.

    PubMed

    Zhao, Binsheng; Tan, Yongqiang; Bell, Daniel J; Marley, Sarah E; Guo, Pingzhen; Mann, Helen; Scott, Marietta L J; Schwartz, Lawrence H; Ghiorghiu, Dana C

    2013-06-01

    Understanding magnitudes of variability when measuring tumor size may be valuable in improving detection of tumor change and thus evaluating tumor response to therapy in clinical trials and care. Our study explored intra- and inter-reader variability of tumor uni-dimensional (1D), bi-dimensional (2D), and volumetric (VOL) measurements using manual and computer-aided methods (CAM) on CT scans reconstructed at different slice intervals. Raw CT data from 30 patients enrolled in oncology clinical trials was reconstructed at 5, 2.5, and 1.25 mm slice intervals. 118 lesions in the lungs, liver, and lymph nodes were analyzed. For each lesion, two independent radiologists manually and, separately, using computer software, measured the maximum diameter (1D), maximum perpendicular diameter, and volume (CAM only). One of them blindly repeated the measurements. Intra- and inter-reader variability for the manual method and CAM were analyzed using linear mixed-effects models and Bland-Altman method. For the three slice intervals, the maximum coefficients of variation for manual intra-/inter-reader variability were 6.9%/9.0% (1D) and 12.3%/18.0% (2D), and for CAM were 5.4%/9.3% (1D), 11.3%/18.8% (2D) and 9.3%/18.0% (VOL). Maximal 95% reference ranges for the percentage difference in intra-reader measurements for manual 1D and 2D, and CAM VOL were (-15.5%, 25.8%), (-27.1%, 51.6%), and (-22.3%, 33.6%), respectively. Variability in measuring the diameter and volume of solid tumors, manually and by CAM, is affected by CT slice interval. The 2.5mm slice interval provides the least measurement variability. Among the three techniques, 2D has the greatest measurement variability compared to 1D and 3D. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  9. Comparing the responsiveness of a brief, multidimensional risk screening tool for back pain to its unidimensional reference standards: the whole is greater than the sum of its parts.

    PubMed

    Wideman, Timothy H; Hill, Jonathan C; Main, Chris J; Lewis, Martyn; Sullivan, Michael J L; Hay, Elaine M

    2012-11-01

    Back pain is a leading cause of disability. Previous research suggests that modifiable risk factors influence recovery from back pain, and practice guidelines recommend integrating such factors within primary care management. Toward this goal, a brief, multidimensional questionnaire, the STarT Back Tool, was designed to facilitate risk assessment by reducing the need to administer multiple, unidimensional questionnaires. However, aspects of this tool's clinical utility remain unaddressed. For instance, it is unclear whether this tool is responsive to treatment-related changes or whether clinically meaningful information is lost when it replaces multiple risk questionnaires. This study compared the responsiveness of the STarT Back Tool to its corresponding full-length measures, and evaluated its ability to detect clinically meaningful improvement. The study sample included 300 participants that consulted their doctor with disabling back pain. The STarT Back Tool and its reference standard questionnaires (disability, catastrophizing, fear, and depression) were administered at baseline and 4 months later. Regression analyses tested whether, after controlling for its reference standard questionnaires, the STarT Back Tool (independent variable) predicted treatment-related changes in global improvement, pain severity, disability, catastrophizing, fear, and depression (dependent variables). Receiver operating characteristic analyses determined the level of STarT Back change needed for clinically meaningful improvement. STarT Back scores predicted changes in all dependent variables except depression. Reductions in STarT Back scores predicted meaningful improvement on all dependent variables. These findings suggest that the STarT Back Tool, instead of multiple risk questionnaires, can be used to measure recovery from back pain. Implications for future research and clinical practice are discussed.

  10. Measuring upper limb capacity in poststroke patients: development, fit of the monotone homogeneity model, unidimensionality, fit of the double monotonicity model, differential item functioning, internal consistency, and feasibility of the stroke upper limb capacity scale, SULCS.

    PubMed

    Roorda, Leo D; Houwink, Annemieke; Smits, Wendy; Molenaar, Ivo W; Geurts, Alexander C

    2011-02-01

    To develop an easy-to-use scale that measures upper limb capacity, according to the International Classification of Functioning, Disability and Health definition, in patients after stroke, and to investigate certain psychometric properties of this scale. Cohort study. Inpatient department of a rehabilitation center. Patients (N=546; mean age ± SD, 60.1±11.2y; 56% men) undergoing rehabilitation after stroke. Not applicable. Mokken scale analysis was used to investigate the following psychometric properties: (1) fit of the monotone homogeneity model, indicating that the items form a scale; (2) unidimensionality, indicating that the items measure only 1 concept (or construct); (3) fit of the double monotonicity model, indicating invariant (hierarchical) item ordering; (4) differential item functioning (DIF), indicating the validity of comparison between subgroups; and (5) internal consistency, indicating the degree of interrelatedness of the items. The mean time needed to complete the scale was calculated to indicate (6) feasibility. The Stroke Upper Limb Capacity Scale (SULCS) was developed on the basis of interviews with experts. Ten of 15 items had (1) good fit of the monotone homogeneity model (coefficient H=.88), were (2) unidimensional, and had (3) good fit of the double monotonicity model (coefficient H(T)=.71), (4) absence of DIF (Crit-values <40), and (5) good internal consistency (coefficient ρ=.96). When applying start-and-stop rules, the (6) feasibility of the SULCS was good (6min). The SULCS is an easy-to-use, unidimensional, hierarchical, and internally consistent scale that assesses upper limb capacity in patients after stroke. Copyright © 2011 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  11. A comparative analysis of the categorization of multidimensional stimuli: I. Unidimensional classification does not necessarily imply analytic processing; evidence from pigeons (Columba livia), squirrels (Sciurus carolinensis), and humans (Homo sapiens).

    PubMed

    Wills, A J; Lea, Stephen E G; Leaver, Lisa A; Osthaus, Britta; Ryan, Catriona M E; Suret, Mark B; Bryant, Catherine M L; Chapman, Sue J A; Millar, Louise

    2009-11-01

    Pigeons (Columba livia), gray squirrels (Sciurus carolinensis), and undergraduates (Homo sapiens) learned discrimination tasks involving multiple mutually redundant dimensions. First, pigeons and undergraduates learned conditional discriminations between stimuli composed of three spatially separated dimensions, after first learning to discriminate the individual elements of the stimuli. When subsequently tested with stimuli in which one of the dimensions took an anomalous value, the majority of both species categorized test stimuli by their overall similarity to training stimuli. However some individuals of both species categorized them according to a single dimension. In a second set of experiments, squirrels, pigeons, and undergraduates learned go/no-go discriminations using multiple simultaneous presentations of stimuli composed of three spatially integrated, highly salient dimensions. The tendency to categorize test stimuli including anomalous dimension values unidimensionally was higher than in the first set of experiments and did not differ significantly between species. The authors conclude that unidimensional categorization of multidimensional stimuli is not diagnostic for analytic cognitive processing, and that any differences between human's and pigeons' behavior in such tasks are not due to special features of avian visual cognition.

  12. Regional emissions data base and evaluation system (REDES): Volume 2, Regional emissions evaluation data base (REED)

    SciTech Connect

    Boyd, G.A.; Campbell, A.P.; Davis, M.J.; Veselka, T.D.

    1988-08-01

    A three-volume report has been prepared to document these REDES data bases and computer model. This volume documents the data base for forecasting emissions. This disaggregated forecast data base of energy use and emissions for electric utility and industrial boilers for 1985 through 2010 is called REED (Regional Emissions Evaluation Data Base). The other volumes describe the methodology of the evaluation system and user-driven menu system (Vol. 1) and document the data base that characterizes 21 generic technologies (Vol. 3). All three volumes provide the user with a complete description of REDES, which is designed to forecast the change in emissions that could result from using a particular clean coal technology. The US Department of Energy's Innovative Clean Coal Technology (ICCT) program has solicited proposals from the private sector to demonstrate innovative technologies that allow the clean use of coal as an energy source. The US Department of Energy and the ICCT Source Evaluation Board requested that Argonne National Laboratory develop two data bases and a personal-computer-based model to aid in evaluating the potential for these proposed technologies to reduce environmental residuals. Version 1.0 of the Regional Emissions Data Base and Evaluation System (REDES) is available to the public through the National Energy Software Center. 41 refs., 16 tabs.

  13. National Urbanization Monitoring Assessment (NUMA)

    USGS Publications Warehouse

    Hester, Dave

    2006-01-01

    A core geographic science element of the U.S. Geological Survey's Geographic Analysis and Monitoring (GAM) Program is to monitor land-surface change for the Nation through time. The Nation's land surface is dynamically evolving and transitioning in response to natural and human processes. The need to understand the transformations and locations where changes are taking place, their underlying causes, and the rate at which the transitions are occurring is fundamental to the health and viability of the Nation's natural and developed environments.

  14. Advances in the U.S. Navy Non-hydrostatic Unified Model of the Atmosphere (NUMA): LES as a Stabilization Methodology for High-Order Spectral Elements in the Simulation of Deep Convection

    NASA Astrophysics Data System (ADS)

    Marras, Simone; Giraldo, Frank

    2015-04-01

    The prediction of extreme weather sufficiently ahead of its occurrence impacts society as a whole and coastal communities specifically (e.g. Hurricane Sandy that impacted the eastern seaboard of the U.S. in the fall of 2012). With the final goal of solving hurricanes at very high resolution and numerical accuracy, we have been developing the Non-hydrostatic Unified Model of the Atmosphere (NUMA) to solve the Euler and Navier-Stokes equations by arbitrary high-order element-based Galerkin methods on massively parallel computers. NUMA is a unified model with respect to the following criteria: (a) it is based on unified numerics in that element-based Galerkin methods allow the user to choose between continuous (spectral elements, CG) or discontinuous Galerkin (DG) methods and from a large spectrum of time integrators, (b) it is unified across scales in that it can solve flow in limited-area mode (flow in a box) or in global mode (flow on the sphere). NUMA is the dynamical core that powers the U.S. Naval Research Laboratory's next-generation global weather prediction system NEPTUNE (Navy's Environmental Prediction sysTem Utilizing the NUMA corE). Because the solution of the Euler equations by high order methods is prone to instabilities that must be damped in some way, we approach the problem of stabilization via an adaptive Large Eddy Simulation (LES) scheme meant to treat such instabilities by modeling the sub-grid scale features of the flow. The novelty of our effort lies in the extension to high order spectral elements for low Mach number stratified flows of a method that was originally designed for low order, adaptive finite elements in the high Mach number regime [1]. The Euler equations are regularized by means of a dynamically adaptive stress tensor that is proportional to the residual of the unperturbed equations. Its effect is close to none where the solution is sufficiently smooth, whereas it increases elsewhere, with a direct contribution to the

  15. Rainfall Erosivity Database on the European Scale (REDES): A product of a high temporal resolution rainfall data collection in Europe

    NASA Astrophysics Data System (ADS)

    Panagos, Panos; Ballabio, Cristiano; Borrelli, Pasquale; Meusburger, Katrin; Alewell, Christine

    2016-04-01

    The erosive force of rainfall is expressed as rainfall erosivity. Rainfall erosivity considers the rainfall amount and intensity, and is most commonly expressed as the R-factor in the (R)USLE model. The R-factor is calculated from a series of single storm events by multiplying the total storm kinetic energy with the measured maximum 30-minutes rainfall intensity. This estimation requests high temporal resolution (e.g. 30 minutes) rainfall data for sufficiently long time periods (i.e. 20 years) which are not readily available at European scale. The European Commission's Joint Research Centre(JRC) in collaboration with national/regional meteorological services and Environmental Institutions made an extensive data collection of high resolution rainfall data in the 28 Member States of the European Union plus Switzerland in order to estimate rainfall erosivity in Europe. This resulted in the Rainfall Erosivity Database on the European Scale (REDES) which included 1,541 rainfall stations in 2014 and has been updated with 134 additional stations in 2015. The interpolation of those point R-factor values with a Gaussian Process Regression (GPR) model has resulted in the first Rainfall Erosivity map of Europe (Science of the Total Environment, 511, 801-815). The intra-annual variability of rainfall erosivity is crucial for modelling soil erosion on a monthly and seasonal basis. The monthly feature of rainfall erosivity has been added in 2015 as an advancement of REDES and the respective mean annual R-factor map. Almost 19,000 monthly R-factor values of REDES contributed to the seasonal and monthly assessments of rainfall erosivity in Europe. According to the first results, more than 50% of the total rainfall erosivity in Europe takes place in the period from June to September. The spatial patterns of rainfall erosivity have significant differences between Northern and Southern Europe as summer is the most erosive period in Central and Northern Europe and autumn in the

  16. Towards estimates of future rainfall erosivity in Europe based on REDES and WorldClim datasets

    NASA Astrophysics Data System (ADS)

    Panagos, Panos; Ballabio, Cristiano; Meusburger, Katrin; Spinoni, Jonathan; Alewell, Christine; Borrelli, Pasquale

    2017-05-01

    The policy requests to develop trends in soil erosion changes can be responded developing modelling scenarios of the two most dynamic factors in soil erosion, i.e. rainfall erosivity and land cover change. The recently developed Rainfall Erosivity Database at European Scale (REDES) and a statistical approach used to spatially interpolate rainfall erosivity data have the potential to become useful knowledge to predict future rainfall erosivity based on climate scenarios. The use of a thorough statistical modelling approach (Gaussian Process Regression), with the selection of the most appropriate covariates (monthly precipitation, temperature datasets and bioclimatic layers), allowed to predict the rainfall erosivity based on climate change scenarios. The mean rainfall erosivity for the European Union and Switzerland is projected to be 857 MJ mm ha-1 h-1 yr-1 till 2050 showing a relative increase of 18% compared to baseline data (2010). The changes are heterogeneous in the European continent depending on the future projections of most erosive months (hot period: April-September). The output results report a pan-European projection of future rainfall erosivity taking into account the uncertainties of the climatic models.

  17. Towards estimates of future rainfall erosivity in Europe based on REDES and WorldClim datasets.

    PubMed

    Panagos, Panos; Ballabio, Cristiano; Meusburger, Katrin; Spinoni, Jonathan; Alewell, Christine; Borrelli, Pasquale

    2017-05-01

    The policy requests to develop trends in soil erosion changes can be responded developing modelling scenarios of the two most dynamic factors in soil erosion, i.e. rainfall erosivity and land cover change. The recently developed Rainfall Erosivity Database at European Scale (REDES) and a statistical approach used to spatially interpolate rainfall erosivity data have the potential to become useful knowledge to predict future rainfall erosivity based on climate scenarios. The use of a thorough statistical modelling approach (Gaussian Process Regression), with the selection of the most appropriate covariates (monthly precipitation, temperature datasets and bioclimatic layers), allowed to predict the rainfall erosivity based on climate change scenarios. The mean rainfall erosivity for the European Union and Switzerland is projected to be 857 MJ mm ha(-1) h(-1) yr(-1) till 2050 showing a relative increase of 18% compared to baseline data (2010). The changes are heterogeneous in the European continent depending on the future projections of most erosive months (hot period: April-September). The output results report a pan-European projection of future rainfall erosivity taking into account the uncertainties of the climatic models.

  18. Understanding Parameter Invariance in Unidimensional IRT Models

    ERIC Educational Resources Information Center

    Rupp, Andre A.; Zumbo, Bruno D.

    2006-01-01

    One theoretical feature that makes item response theory (IRT) models those of choice for many psychometric data analysts is parameter invariance, the equality of item and examinee parameters from different examinee populations or measurement conditions. In this article, using the well-known fact that item and examinee parameters are identical only…

  19. Estimativa de imagens solares soho através de redes neurais artificiais

    NASA Astrophysics Data System (ADS)

    Andrade, M. C.; Fernandes, F. C. R.; Cecatto, J. R.; Rios Neto, A.; Rosa, R. R.; Sawant, H. S.

    2003-08-01

    A Rede Neural Artificial (RNA), no âmbito da teoria computacional, constitui uma teoria emergente que, por possuir habilidade em aprender a partir de dados de entrada, encontra diferentes aplicações em diferentes áreas. Um exemplo é a utilização de RNA na caracterização de padrões associados à dinâmica de processos espaço-temporais relacionados a fenômenos físicos não-lineares. Para obter informações sobre o comportamento destes fenômenos físicos utiliza-se, em diversos casos, seqüências de imagens digitalizadas, onde a caracterização de alguns fenômenos espaço-temporais é o procedimento mais viável para descrever a dinâmica das regiões ativas do Sol. Com base em imagens observadas por telescópios a bordo de satélites, estudos de previsão de eventos solares podem ser programados, permitindo prever possíveis efeitos posteriores nas regiões mais próximas da Terra (tempestades geomagnéticas e irregularidades ionosféricas). Neste trabalho avaliamos o desempenho da RNA para estimar padrões espaço-temporais, ou seja, imagens solares em ultravioleta, obtidas através do telescópio a bordo do satélite SOHO. Os resultados mostraram que as RNA conseguem generalizar os padrões de maneira satisfatória sem perder de forma significativa os principais aspectos da configuração global da atmosfera solar, comprovando a eficácia da RNA como ferramenta para esse tipo de aplicação. Portanto, este trabalho comprova a viabilidade de uso desta ferramenta em projetos voltados ao estudo do comportamento solar, em trabalhos do grupo de Física do Meio Interplanetário (FMI) na DAS e em programas desenvolvidos pelo Núcleo de Simulação e Análise de Sistemas Complexos (NUSASC) do Laboratório Associado de Computação e Matemática Aplicada (LAC) do INPE.

  20. Development of an Unified Atmospheric Model (NUMA)

    DTIC Science & Technology

    2010-08-12

    order mode, primarily used with quads and inexact integration (e.g., using Lobatto points avoids non-diagonal mass matrix with slight error since...integration is O(2N-1)) •  No analog of Lobatto points exist on the triangle so costly to use •  Excellent scalability on MPP Discontinuous...functions: 3D tensor products of Lobatto -Gauss-Legendre (LGL) points. Elements are hexahedra (Triangular prisms coming soon). •  Time-Integrators are

  1. Measurement of arterial input function of 17O water tracer in rat carotid artery by using a region-defined (REDE) implanted vascular RF coil.

    PubMed

    Zhang, Xiaoliang; Zhu, Xiao-Hong; Tian, Runxia; Zhang, Yi; Merkle, Hellmut; Chen, Wei

    2003-07-01

    A method of determining arterial input function (AIF) by continuously detecting the (17)O MR signal changes of (17)O-labeled water tracer in the rat carotid artery using a region-defined (REDE) implanted vascular RF coil at 9.4 Tesla is reported. This coil has a compact physical size of 1 mm inner diameter, 3 mm outer diameter and 11 mm in length. It can be readily implanted into the rat neck and wrapped around the rat carotid artery for achieving adequate MR detection sensitivity for determining AIF with minimal surgical trauma. Water phantom and in vivo MR experiments were conducted for validating the coil's performance. A signal-to-noise ratio of approximately 20:1 was achieved for the (17)O signal acquired from naturally abundant H(2)(17)O in a small amount of blood (approximately 7 microl) inside the rat carotid artery with an acquisition time of 11 s. The REDE RF coil design electromagnetically isolates the rat carotid artery from surrounding tissues and ensures that the MR signal detected by the RF coil is only attributable to the artery blood. It also minimizes the electromagnetic coupling between the implanted RF coil and a head surface coil tuned at the same operating frequency (two-coil configuration). This configuration allowed simultaneous measurements of dynamic changes of (17)O MR signal of the H(2)(17)O tracer in both rat carotid artery and brain. Compared to most contemporary MR approaches, the REDE implanted RF provides a simple, accurate, and promising solution for determination of AIF in small experimental animals.

  2. Health care networks implementation and regional governance challenges in the Legal Amazon Region: an analysis of the QualiSUS-Rede Project.

    PubMed

    Casanova, Angela Oliveira; Cruz, Marly Marques; Giovanella, Ligia; Alves, Glaydes Dos Reis; Cardoso, Gisela Cordeiro Pereira

    2017-04-01

    This paper aims to analyze the potential, limits and challenges of regional governance in the implementation process of health care networks in three Brazilian regions: Alto Solimões (Amazonas), Belém (Pará) and an interstate region comprising Tocantins, Pará and Maranhão states (Topama). The study is based on the evaluation study on the implementation of the Quality Health Care Network Development and Improvement Project (QualiSUS-Rede). This is a qualitative multiple case study with the analysis of official documents and use of semi-structured interviews with key stakeholders conducted from July to December 2014. Governance review encompassed three components: stakeholders involved, especially local steering groups and their regional coordination capacity; strategies used for strengthening regional governance, anchored on the intervention's modeling; and implementation of local health care networks. Results point that the regional managing commissions were the main governance strategy and that the QualiSUS-Rede Project strengthened regional governance and integration differently in every case, depending on stakeholders' administration and consensus capacity on regional and political priorities.

  3. Quaternary glacial geomorphosites from the Cantabrian Mountains (northern Iberian Peninsula): the Redes Natural Reservation and Picos de Europa Regional Park

    NASA Astrophysics Data System (ADS)

    Rodríguez-Rodríguez, Laura; Jiménez-Sánchez, Montserrat; José Domínguez-Cuesta, María

    2013-04-01

    The Cantabrian Mountains is a mountain range 480 km-long and up to 2,648 m altitude (Torre Cerredo Peak) trending parallel to the Cantabrian Coastline between Pyrenees and the northwest corner of the Iberian Peninsula (~43oN 5oW). This mountain range is an outstanding area to research the climatic patterns across South Europe during the Quaternary glaciations since well-preserved glacial features evidence the occurrence of past mountain glaciations in a climatic environment marked by the transition from a maritime climate (Atlantic) to Mediterranean one across the mountain range. The available studies in the Cantabrian Mountains stand that the regional glacial maximum recorded here is prior to ca 38, and that glaciers were in some locations remarkably retreated by the time of the global Last Glacial Maximum (Jiménez-Sánchez et al., in press; Serrano et al., in press). This study is focused on an area about 800 km2 that includes 36 peaks over 2,000 m (Pico Mampodre; 2,192 m) and partially covers the Redes Natural Reservation and Picos de Europa Regional Park. A geomorphologic database in ArcGIS was produced for this area as a previous step to reconstruct in detail the extent, flow pattern and chronology of the former glaciers (PhD under progress). Here we present a selection of 18 glacial geomorphosites classified according to genetic criteria in sites that show: (i) a nicely preserved moraine sequence recording the transition from glacial to periglacial conditions; (ii) glacial erosion features; (iii) glacial and ice related deposits (like moraines, ice-dammed deposits, erratic boulders or fluvio-glacial deposits); (iv) slope instability related to glacial debuttressing (complex landslides and rock avalanches); and (v) the interaction between the landscape and human activity. The interest of the geomorphosites is supported by its good quality of preservation, allowing its use as a basis to reconstruct the glacial and paraglacial processes in this region during

  4. Assessing Fit of Unidimensional Graded Response Models Using Bayesian Methods

    ERIC Educational Resources Information Center

    Zhu, Xiaowen; Stone, Clement A.

    2011-01-01

    The posterior predictive model checking method is a flexible Bayesian model-checking tool and has recently been used to assess fit of dichotomous IRT models. This paper extended previous research to polytomous IRT models. A simulation study was conducted to explore the performance of posterior predictive model checking in evaluating different…

  5. Shape determination of unidimensional objects: the virtual image correlation method

    NASA Astrophysics Data System (ADS)

    Francois, M.; Semin, B.; Auradou, H.; Vatteville, J.

    2010-06-01

    The proposed method, named Virtual Image Correlation, allows one to identify an analytical expression of the shape of a curvilinear object from its image. It uses a virtual beam, whose curvature field is expressed as a truncated mathematical series. The virtual beam width only needs to be close to the physical one; its gray level (in the transverse direction) is bell-shaped. The method consists in finding the coefficients of the series for which the correlation between physical and virtual beams is the best. The accuracy and the robustness of the method is shown by the mean of two examples. The first details a Young’s modulus identification from a cantilever beam image. The second is relative to a thermal plume image, that have a weak contrast and a lot of noise.

  6. Unidimensional and Multidimensional Models for Item Response Theory.

    ERIC Educational Resources Information Center

    McDonald, Roderick P.

    This paper provides an up-to-date review of the relationship between item response theory (IRT) and (nonlinear) common factor theory and draws out of this relationship some implications for current and future research in IRT. Nonlinear common factor analysis yields a natural embodiment of the weak principle of local independence in appropriate…

  7. Controlling chaos in unidimensional maps using macroevolutionary algorithms.

    PubMed

    Marín, Jesús; Solé, Ricard V

    2002-02-01

    We introduce a simple search algorithm that explores the parameter of periodically perturbed discrete maps in order to find desired orbits through chaos control. The method has been applied to one-dimensional maps but is easily extendable to higher-dimensional systems. Here, we consider two types of chaos control involving proportional pulses in the system variables [Phys. Rev. Lett. 72, 1455 (1994)] and constant feedback [Phys. Rev. E 51, 6239 (1995)], the first case being presented in detail. It is shown that our method allows a rapid exploration of parameter space and the finding of high-fitness (i.e., controlled) solutions close to the target orbits, even when high periodicities are required.

  8. Bias Coefficients for Lack of Invariance in Unidimensional IRT Models.

    ERIC Educational Resources Information Center

    Rupp, Andre A.; Zumbo, Bruno D.

    The feature that makes item response theory (IRT) models the models of choice for many psychometric data analysts is parameter invariance, the equality of item and examinee parameters from different populations. Using the well-known fact that item and examinee parameters are identical only up to a set of linear transformations specific to the…

  9. Limitations of Coefficient Alpha as an Index of Test Unidimensionality

    ERIC Educational Resources Information Center

    Green, Samual B.; And Others

    1977-01-01

    Confusion in the literature between the concepts of internal consistency and homogeneity has led to a misuse of coefficient alpha as an index of item homogeneity. This misuse is discussed and several indices of item homogeneity derived from the model of common factor analysis are offered as alternatives. (Author/JKS)

  10. The Oral Health Impact Profile-14: a unidimensional scale?

    PubMed

    Santos, Camila Mello dos; Oliveira, Branca Heloisa de; Nadanovsky, Paulo; Hilgert, Juliana Balbinot; Celeste, Roger Keller; Hugo, Fernando Neves

    2013-04-01

    The aim of this study was to investigate the dimensional structure of the Oral Health Impact Profile-14: (OHIP-14). Data was obtained from studies carried out in Rio de Janeiro (N = 504) and Carlos Barbosa (N = 872), in the State of Rio Grande do Sul, Brazil. Exploratory factor analysis (EFA) was performed to identify the latent dimensions of the OHIP-14. Confirmatory factor analysis (CFA) was carried out of both samples to compare the one-dimensional structure found by the EFA and the proposed three-dimensional structure. This factorial structure was assessed using goodness-of-fit indices. In the Rio de Janeiro study, the eigenvalue was 9.2 and this one factor explained 65.6% of total variance, while in the Carlos Barbosa study the eigenvalue was 7.9 and this one factor explained 56.6% of variance. CFA indicated an adequate fit of the one-factor model for the Rio de Janeiro study (RMSEA = 0.04; CFI = 0.98; TLI = 0.98) and for the Carlos Barbosa study (RMSEA = 0.05; CFI = 0.97; TLI = 0.97). Our findings suggest that the OHIP-14 measures one single construct.

  11. [Strategies for integration of health care practices and sanitary surveillance in the context of the implementation of Rede Cegonha - a Brazilian mother and infant health care network].

    PubMed

    Fernandes, Roberta Zanelli Sartori; Vilela, Maria Filomena de Gouveia

    2014-11-01

    Mother and infant mortality has been the scope of analysis throughout the history of public health in Brazil and various strategies to tackle the issue have been proposed to date. The Ministry of Health has been working on this and the Rede Cegonha strategy is the most recent policy in this context. Given the principle of comprehensive health care and the structure of the Unified Health System in care networks, it is necessary to ensure the integration of health care practices, among which are the sanitary surveillance actions (SSA). Considering that the integration of health care practices and SSA can contribute to reduce mother and infant mortality rates, this article is a result of qualitative research that analyzed the integration of these actions in four cities in the State of São Paulo/Brazil: Campinas, Indaiatuba, Jaguariúna and Santa Bárbara D'Oeste. The research was conducted through interviews with SSA and maternal health managers, and the data were evaluated using thematic analysis. The results converge with other studies, identifying the isolation of health care practices and SSA. The insertion of SSA in collectively-managed areas appears to be a potential strategy for health planning and implementation of actions in the context under scrutiny.

  12. Economic evaluation of the Programs Rede Farmácia de Minas do SUS versus Farmácia Popular do Brasil.

    PubMed

    Garcia, Marina Morgado; Guerra, Augusto Afonso; Acúrcio, Francisco de Assis

    2017-01-01

    We conducted an economic assessment of the Pharmaceutical Assistance - Rede Farmácia de Minas Gerais-RFMG and Farmácia Popular do Brasil-FPB to ascertain which of the two models stands out as the most efficient. To do this, a model, which consisted of a study of incurred costs in both programs, up to the dispensing of medicine to citizens, was developed. The uncertainties of the proposed model were tested using the Monte Carlo method. If the entire population initially estimated in the RFMG were attended in the FPB, there would be an additional cost of R$ 139,324,050.19. The sensitivity analysis appeared to be favorable to the RFMG. A total of 10000 simulations were carried out, resulting in a median value of R$ 114,053,709.99 for the RFMG and R$ 254,106,120.65 for the FPB. The current National Drug Policy emphasizes the need to strengthen pharmaceutical services beyond the mere acquisition and delivery of pharmaceutical products. The public healthcare service model, consistent with the principles and guidelines of the SUS, seems to be more appropriate in ensuring complete and universal quality healthcare services to the citizens. The economic study conducted reinforces this fact, as it appears to be a more efficient alternative of the direct use of resources in the public health network.

  13. An update on the Kevorkian-Reding 93 physician-assisted deaths in Michigan: is Kevorkian a savior, serial-killer or suicidal martyr?

    PubMed

    Kaplan, K J; O'Dell, J; Dragovic, L J; McKeon, M C; Bentley, E; Telmet, K L

    This report presents an update of the Kevorkian-Reding physician-assisted (or physician-aided) deaths to include the ninety-three publicly acknowledged cases as of November 25, 1998. These deaths are divided into ten distinct time phases. The following trends emerge. Over two-thirds of the decedents are women, the ratio of females to males varying widely with phase. The proportion of women seems to be the highest when Kevorkian is free to act as he wants and lowest when he seems to be acting under legal or political restraints. Based on autopsy results, only 29.0 percent of the cases are terminal, this percentage being higher among men (37.9%) than among women (25.4%). However, 66.7% of the decedents were disabled, no significant difference emerging between men and women. Further, five out of the six decedents showing no apparent anatomical sign of disease at autopsy were women. Over 80 percent of the physician-assisted deaths are cremated, approximately twice as high a proportion as that emerging for suicides in Michigan and four times as high as cremations occurring with regard to overall deaths. Finally, death by carbon monoxide decreases dramatically with time phase while the use of the contraption dubbed the "suicide machine" increases, suggesting an increasing routinization over time. Finally, during the ninth and tenth phases, Kevorkian's aims and his own suicidality emerge more clearly involving 1) harvesting organs and 2) threat of starving himself in prison if he is convicted. Phase 10 can be seen as an escalation from assisted death to overt euthanasia, repeating the same need for a demonstration (Thomas Youk) that was first exhibited in Phase I (Janet Adkins).

  14. Como os Alunos do Ensino Médio da Rede Estadual de São Paulo obtém Conhecimentos Astronômicos?

    NASA Astrophysics Data System (ADS)

    da Cunha, W. S.; Voelzke, M. R.; Amaral, L. H.

    2005-08-01

    Atualmente vivencia-se um mundo globalizado onde os computadores e a internet permitiram um acesso rápido e seguro a todo tipo de informação e conhecimento. O presente trabalho visa analisar a maneira pela qual alunos de segundo grau da rede estadual da cidade de São Paulo obtiveram, caso tenham, conhecimentos básicos de astronomia quanto aos fenômenos celestes que os rodeiam, tais como a sucessão dos dias e das estações do ano, além de questioná~los sobre fatos genéricos tais como: o que vem a ser o Sol, o Big Bang, o que ocasionou a extinção dos dinossauros. Para tanto foi elaborado um formulário constando de questões de múltipla escolha, o qual foi aplicado no primeiro colegial diurno da Escola Estadual Guilherme de Almeida. Num espaço amostral de 44 alunos constatou-se que 41% dos alunos adquiriram seus conhecimentos astronômicos na escola e 59% através da mídia em geral. Neste mesmo espaço amostral apenas 11% dos alunos usaram computadores na escola, 41% na residência, 5% no trabalho e 43% não utilizaram. O presente estudo revelou também que para 50% dos alunos o professor jamais utilizou um programa de computador a respeito de astronomia ou fez alguma apresentação sobre o tema. Embora em sua fase inicial este estudo revela claramente que a maioria dos alunos não obtém na escola seus conhecimentos astronômicos, estes provém de fontes não especificamente didático-pedagógicas tais como filmes e revistas populares que não raramente geram conhecimentos incompletos e em muitos casos inclusive falhos.

  15. Percepção Astronômica de Alunos do Ensino Médio da Rede Estadual de São Paulo

    NASA Astrophysics Data System (ADS)

    de Oliveira, E. F.; Voelzke, M. R.; Amaral, L. H.

    2005-08-01

    Embora a astronomia seja uma das ciências mais antigas da humanidade e muitos dos conceitos astronômicos serem populares, principalmente nesta época de alta globalização do conhecimento por intermédio de eficientes meios de comunicação e de obtenção da informação, notadamente através da internet, observa-se que uma parcela significativa dos estudantes encontra-se à margem dessas informações. O presente trabalho visa analisar o nível de conhecimento básico dos alunos de Ensino Médio da rede estadual da cidade de Suzano quanto aos fenômenos astronômicos que os rodeiam, tais como a sucessão dos dias e das estações do ano, além de questioná-los sobre fatos genéricos tais como: quais são os astros que se encontram mais próximos do planeta Terra, o que vem a ser o Sol, o Big Bang, um ano-luz, uma estrela cadente, a estrela de Bélem e o que ocasionou a extinção dos dinossauros. Para tanto foi elaborado um formulário constando de questões de múltipla escolha, o qual foi aplicado no primeiro colegial noturno da Escola Estadual Batista Renzi. Num espaço amostral de 34 alunos constatou-se que apenas 29,4% compreendiam a sucessão dos dias da semana, que apenas 20,6% explicaram corretamente as estações do ano, que apenas 20,6% tinham idéia de quais são os objetos celestes mais próximos da Terra, em contraposição 67,6% sabiam classificar corretamente o Sol como estrela, 55,9% relacionavam o Big Bang à origem do universo, apenas 20,6% identificavam um ano-luz como unidade de distância, 32,4% reconheciam uma estrela cadente como meteoro, 41,2% consideravam a estrela de Belém como um cometa e 50,0% explicaram corretamente a extinção dos dinossauros. A presente análise será expandida para as demais classes de primeiro colegial, não somente do período noturno, mas também do diurno da Escola Estadual Batista Renzi, bem como o formulário será devidamente ampliado. Já nesta primeira fase nota-se claramente o pequeno discernimento

  16. Evaluation of dose reduction versus standard dosing for maintenance of remission in patients with spondyloarthritis and clinical remission with anti-TNF (REDES-TNF): study protocol for a randomized controlled trial.

    PubMed

    Pontes, Caridad; Gratacós, Jordi; Torres, Ferran; Avendaño, Cristina; Sanz, Jesús; Vallano, Antoni; Juanola, Xavier; de Miguel, Eugenio; Sanmartí, Raimon; Calvo, Gonzalo

    2015-08-20

    Dose reduction schedules of tumor necrosis factor antagonists (anti-TNF) as maintenance therapy in patients with spondyloarthritis are used empirically in clinical practice, despite the lack of clinical trials providing evidence for this practice. To address this issue the Spanish Society of Rheumatology (SER) and Spanish Society of Clinical Pharmacology (SEFC) designed a 3-year multicenter, randomized, open-label, controlled clinical trial (2 years for inclusion and 1 year of follow-up). The study is expected to include 190 patients with axial spondyloarthritis on stable maintenance treatment (≥4 months) with any anti-TNF agent at doses recommended in the summary of product characteristics. Patients will be randomized to either a dose reduction arm or maintenance of the dosing regimen as per the official labelling recommendations. Randomization will be stratified according to the anti-TNF agent received before study inclusion. Patient follow-up, visit schedule, and examinations will be maintained as per normal clinical practice recommendations according to SER guidelines. The study aims to test the hypothesis of noninferiority of the dose reduction strategy compared with standard treatment. The first patients were recruited in July 2012, and study completion is scheduled for the end of April 2015. The REDES-TNF study is a pragmatic clinical trial that aims to provide evidence to support a medical decision now made empirically. The study results may help inform clinical decisions relevant to both patients and healthcare decision makers. EudraCT 2011-005871-18 (21 December 2011).

  17. Psychometric Characteristics of Integrated Multi-Specialty Examinations: Ebel Ratings and Unidimensionality

    ERIC Educational Resources Information Center

    Homer, Matt; Darling, Jonathan; Pell, Godfrey

    2012-01-01

    Over recent years, UK medical schools have moved to more integrated summative examinations. This paper analyses data from the written assessment of undergraduate medical students to investigate two key psychometric aspects of this type of high-stakes assessment. Firstly, the strength of the relationship between examiner predictions of item…

  18. Applying Unidimensional and Multidimensional Item Response Theory Models in Testlet-Based Reading Assessment

    ERIC Educational Resources Information Center

    Min, Shangchao; He, Lianzhen

    2014-01-01

    This study examined the relative effectiveness of the multidimensional bi-factor model and multidimensional testlet response theory (TRT) model in accommodating local dependence in testlet-based reading assessment with both dichotomously and polytomously scored items. The data used were 14,089 test-takers' item-level responses to the testlet-based…

  19. Bias of Exploratory and Cross-Validated DETECT Index under Unidimensionality

    ERIC Educational Resources Information Center

    Monahan, Patrick O.; Stump, Timothy E.; Finch, Holmes; Hambleton, Ronald K.

    2007-01-01

    DETECT is a nonparametric "full" dimensionality assessment procedure that clusters dichotomously scored items into dimensions and provides a DETECT index of magnitude of multidimensionality. Four factors (test length, sample size, item response theory [IRT] model, and DETECT index) were manipulated in a Monte Carlo study of bias, standard error,…

  20. The Analysis of Dominance Matrices: Extraction of Unidimensional Orders within a Multidimensional Context

    DTIC Science & Technology

    1976-06-01

    index of dimension consistency that is comparable to classical measures such as the Kuder - Richardson formulae (1937) and the Loevinger homogeneity...1975b) is a measure of internal con- sistency calculated from a dominance matrix that functions like the standard Kuder - Richardson formulae (KR...corresponds directly to such classical indices as the Kuder - Richardson formulae (1937) like the internal consistency index proposed by Cliff (1975b

  1. Rational Synthesis of New Unidimensional Solids: Chemical and Physical Studies of Mixed Valence Polyiodides.

    DTIC Science & Technology

    1977-12-28

    further structural definition of changes induced by iodination, and extension of physicochemical measurements. The spectroscopic results on Ni(bqd)2...presence of multiple redox states, and the inherent chemical flexibility of phthalo- cyanines suggested attractive donor molecules for the

  2. Limits on Log Odds Ratios for Unidimensional Item Response Theory Models

    ERIC Educational Resources Information Center

    Haberman, Shelby J.; Holland, Paul W.; Sinharay, Sandip

    2007-01-01

    Bounds are established for log odds ratios (log cross-product ratios) involving pairs of items for item response models. First, expressions for bounds on log odds ratios are provided for one-dimensional item response models in general. Then, explicit bounds are obtained for the Rasch model and the two-parameter logistic (2PL) model. Results are…

  3. Exploratory Mokken Scale Analysis as a Dimensionality Assessment Tool: Why Scalability Does Not Imply Unidimensionality

    ERIC Educational Resources Information Center

    Smits, Iris A. M.; Timmerman, Marieke E.; Meijer, Rob R.

    2012-01-01

    The assessment of the number of dimensions and the dimensionality structure of questionnaire data is important in scale evaluation. In this study, the authors evaluate two dimensionality assessment procedures in the context of Mokken scale analysis (MSA), using a so-called fixed lowerbound. The comparative simulation study, covering various…

  4. Unidimensional IRT Item Parameter Estimates across Equivalent Test Forms with Confounding Specifications within Dimensions

    ERIC Educational Resources Information Center

    Matlock, Ki Lynn; Turner, Ronna

    2016-01-01

    When constructing multiple test forms, the number of items and the total test difficulty are often equivalent. Not all test developers match the number of items and/or average item difficulty within subcontent areas. In this simulation study, six test forms were constructed having an equal number of items and average item difficulty overall.…

  5. Unidimensional versus Multidimensional Approaches to the Assessment of Acculturation for Asian American Populations.

    ERIC Educational Resources Information Center

    Abe-Kim, Jennifer; Okazaki, Sumie; Goto, Sharon G.

    2001-01-01

    Examines approaches to assessing acculturation among Asian Americans college students in relation to the cultural indicators of individualism-collectivism, self-construal, impression management, and loss of face. An uneven nature of these relationships was found which is significant in light of the fact that acculturation differences are often…

  6. A GPU-Based Gibbs Sampler for a Unidimensional IRT Model.

    PubMed

    Sheng, Yanyan; Welling, William S; Zhu, Michelle M

    2014-01-01

    Item response theory (IRT) is a popular approach used for addressing large-scale statistical problems in psychometrics as well as in other fields. The fully Bayesian approach for estimating IRT models is usually memory and computationally expensive due to the large number of iterations. This limits the use of the procedure in many applications. In an effort to overcome such restraint, previous studies focused on utilizing the message passing interface (MPI) in a distributed memory-based Linux cluster to achieve certain speedups. However, given the high data dependencies in a single Markov chain for IRT models, the communication overhead rapidly grows as the number of cluster nodes increases. This makes it difficult to further improve the performance under such a parallel framework. This study aims to tackle the problem using massive core-based graphic processing units (GPU), which is practical, cost-effective, and convenient in actual applications. The performance comparisons among serial CPU, MPI, and compute unified device architecture (CUDA) programs demonstrate that the CUDA GPU approach has many advantages over the CPU-based approach and therefore is preferred.

  7. Providing Subscale Scores for Diagnostic Information: A Case Study when the Test Is Essentially Unidimensional

    ERIC Educational Resources Information Center

    Stone, Clement A.; Ye, Feifei; Zhu, Xiaowen; Lane, Suzanne

    2010-01-01

    Although reliability of subscale scores may be suspect, subscale scores are the most common type of diagnostic information included in student score reports. This research compared methods for augmenting the reliability of subscale scores for an 8th-grade mathematics assessment. Yen's Objective Performance Index, Wainer et al.'s augmented scores,…

  8. A GPU-Based Gibbs Sampler for a Unidimensional IRT Model

    PubMed Central

    Welling, William S.; Zhu, Michelle M.

    2014-01-01

    Item response theory (IRT) is a popular approach used for addressing large-scale statistical problems in psychometrics as well as in other fields. The fully Bayesian approach for estimating IRT models is usually memory and computationally expensive due to the large number of iterations. This limits the use of the procedure in many applications. In an effort to overcome such restraint, previous studies focused on utilizing the message passing interface (MPI) in a distributed memory-based Linux cluster to achieve certain speedups. However, given the high data dependencies in a single Markov chain for IRT models, the communication overhead rapidly grows as the number of cluster nodes increases. This makes it difficult to further improve the performance under such a parallel framework. This study aims to tackle the problem using massive core-based graphic processing units (GPU), which is practical, cost-effective, and convenient in actual applications. The performance comparisons among serial CPU, MPI, and compute unified device architecture (CUDA) programs demonstrate that the CUDA GPU approach has many advantages over the CPU-based approach and therefore is preferred. PMID:27355058

  9. Order-Constrained Bayes Inference for Dichotomous Models of Unidimensional Nonparametric IRT

    ERIC Educational Resources Information Center

    Karabatsos, George; Sheu, Ching-Fan

    2004-01-01

    This study introduces an order-constrained Bayes inference framework useful for analyzing data containing dichotomous scored item responses, under the assumptions of either the monotone homogeneity model or the double monotonicity model of nonparametric item response theory (NIRT). The framework involves the implementation of Gibbs sampling to…

  10. The Factorial Validity of Trait Positive Affect Scores: Confirmatory Factor Analyses of Unidimensional and Multidimensional Models.

    ERIC Educational Resources Information Center

    Roesch, Scott C.

    1998-01-01

    First- and second-order confirmatory factor analyses were conducted to evaluate the factorial validity of scores on two positive affect (PA) measurement instruments and a multidimensional representation of PA using a sample of 232 undergraduates. Both measures were well represented by multifactorial models, and each was represented well by a…

  11. The Assessment of Unidimensionality of Normal and Lognormal Data: A Look at Two Nonparametric Procedures.

    ERIC Educational Resources Information Center

    Seraphine, Anne E.; Algina, James J.; Miller, M. David

    2001-01-01

    Examined the Type I error rate and the power of the Stout T procedure (DIMTEST) (W. Stout, 19987, 1990) and the Holland-Rosenbaum procedure (P. Holland and P. Rosenbaum, 1986) for normal and nonnormal data sets through a Monte Carlo study. Both procedures performed adequately under some conditions, but the Stout T procedure showed adequate power…

  12. Unidimensional IRT Item Parameter Estimates across Equivalent Test Forms with Confounding Specifications within Dimensions

    ERIC Educational Resources Information Center

    Matlock, Ki Lynn; Turner, Ronna

    2016-01-01

    When constructing multiple test forms, the number of items and the total test difficulty are often equivalent. Not all test developers match the number of items and/or average item difficulty within subcontent areas. In this simulation study, six test forms were constructed having an equal number of items and average item difficulty overall.…

  13. A New Item Response Theory Modeling Approach with Applications to Unidimensionality Assessment and Ability Estimation

    DTIC Science & Technology

    1989-03-01

    each subtest (Ui 1 ,.,Ui ) of 4 (here by definition !1 !2 if and only if 0li 5 #i for each coordinate i; also 1 < i1 < ... < ik 5 N). The model is said...dO. (3) 2. A New Concevtualization of Test Dimensionalitv. Let us recall the traditional IRT definition of test dimensionality that almost always...applies in IRT models: Definition 2.1. The dimensionality d of a test U. is the minimal dimen- sionality required for E to produce a latent model (U, 2

  14. Applying Unidimensional and Multidimensional Item Response Theory Models in Testlet-Based Reading Assessment

    ERIC Educational Resources Information Center

    Min, Shangchao; He, Lianzhen

    2014-01-01

    This study examined the relative effectiveness of the multidimensional bi-factor model and multidimensional testlet response theory (TRT) model in accommodating local dependence in testlet-based reading assessment with both dichotomously and polytomously scored items. The data used were 14,089 test-takers' item-level responses to the testlet-based…

  15. The Graded Unfolding Model: A Unidimensional Item Response Model for Unfolding Graded Responses.

    ERIC Educational Resources Information Center

    Roberts, James S.; Laughlin, James E.

    Binary or graded disagree-agree responses to attitude items are often collected for the purpose of attitude measurement. Although such data are sometimes analyzed with cumulative measurement models, recent investigations suggest that unfolding models are more appropriate (J. S. Roberts, 1995; W. H. Van Schuur and H. A. L. Kiers, 1994). Advances in…

  16. A Unidimensional Item Response Model for Unfolding Responses from a Graded Disagree-Agree Response Scale.

    ERIC Educational Resources Information Center

    Roberts, James S.; Laughlin, James E.

    1996-01-01

    A parametric item response theory model for unfolding binary or graded responses is developed. The graded unfolding model (GUM) is a generalization of the hyperbolic cosine model for binary data of D. Andrich and G. Luo (1993). Applicability of the GUM to attitude testing is illustrated with real data. (SLD)

  17. Bias of Exploratory and Cross-Validated DETECT Index under Unidimensionality

    ERIC Educational Resources Information Center

    Monahan, Patrick O.; Stump, Timothy E.; Finch, Holmes; Hambleton, Ronald K.

    2007-01-01

    DETECT is a nonparametric "full" dimensionality assessment procedure that clusters dichotomously scored items into dimensions and provides a DETECT index of magnitude of multidimensionality. Four factors (test length, sample size, item response theory [IRT] model, and DETECT index) were manipulated in a Monte Carlo study of bias, standard error,…

  18. The Robustness of IRT-Based Vertical Scaling Methods to Violation of Unidimensionality

    ERIC Educational Resources Information Center

    Yin, Liqun

    2013-01-01

    In recent years, many states have adopted Item Response Theory (IRT) based vertically scaled tests due to their compelling features in a growth-based accountability context. However, selection of a practical and effective calibration/scaling method and proper understanding of issues with possible multidimensionality in the test data is critical to…

  19. Between-Person and Within-Person Subscore Reliability: Comparison of Unidimensional and Multidimensional IRT Models

    ERIC Educational Resources Information Center

    Bulut, Okan

    2013-01-01

    The importance of subscores in educational and psychological assessments is undeniable. Subscores yield diagnostic information that can be used for determining how each examinee's abilities/skills vary over different content domains. One of the most common criticisms about reporting and using subscores is insufficient reliability of subscores.…

  20. Exploratory Mokken Scale Analysis as a Dimensionality Assessment Tool: Why Scalability Does Not Imply Unidimensionality

    ERIC Educational Resources Information Center

    Smits, Iris A. M.; Timmerman, Marieke E.; Meijer, Rob R.

    2012-01-01

    The assessment of the number of dimensions and the dimensionality structure of questionnaire data is important in scale evaluation. In this study, the authors evaluate two dimensionality assessment procedures in the context of Mokken scale analysis (MSA), using a so-called fixed lowerbound. The comparative simulation study, covering various…

  1. Normal Scaling of the Unidimensional Dominance Matrices: The Domain Referenced Model

    ERIC Educational Resources Information Center

    Krus, David J.; Krus, Patricia H.

    1977-01-01

    Described is a Fortran computer program for an alternative algorithm for Thurstone's pair comparisons method. This algorithm provides an improved capacity for handling indeterminate proportions of one and zero as well as untruncated estimates of population scale values. (Author/JKS)

  2. Matrix Reorganization and Dynamic Programming: Applications to Paired Comparisons and Unidimensional Seriation.

    ERIC Educational Resources Information Center

    Hubert, L. J.; Golledge, R. G.

    1981-01-01

    A recursive dynamic programing strategy for reorganizing the rows and columns of square proximity matrices is discussed. The strategy is used when the objective function measuring the adequacy of the reorganization has a fairly simple additive structure. (Author/JKS)

  3. Unrestricted Factor Analytic Procedures for Assessing Acquiescent Responding in Balanced, Theoretically Unidimensional Personality Scales

    ERIC Educational Resources Information Center

    Ferrando, Pere J.; Lorenzo-Seva, Urbano; Chico, Eliseo

    2003-01-01

    This article describes and proposes an unrestricted factor analytic procedure to: (a) assess the dimensionality and structure of a balanced personality scale taking into account the potential effects of acquiescent responding, and (b) correct the individual trait estimates for acquiescence. The procedure can be considered as an extension of ten…

  4. Psychometric Characteristics of Integrated Multi-Specialty Examinations: Ebel Ratings and Unidimensionality

    ERIC Educational Resources Information Center

    Homer, Matt; Darling, Jonathan; Pell, Godfrey

    2012-01-01

    Over recent years, UK medical schools have moved to more integrated summative examinations. This paper analyses data from the written assessment of undergraduate medical students to investigate two key psychometric aspects of this type of high-stakes assessment. Firstly, the strength of the relationship between examiner predictions of item…

  5. The Development of the Non-hydrostatic Unified Model of the Atmosphere (NUMA)

    DTIC Science & Technology

    2011-09-19

    response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and... reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including...Modeling Mode Global Modeling Mode (Cubed-Sphere) Global Modeling Mode (Icosahedral) Telescoping Grid ITCZ Grid Results: Mesoscale Mode (3D

  6. The Confounding Effects of Ability, Item Difficulty, and Content Balance within Multiple Dimensions on the Estimation of Unidimensional Thetas

    ERIC Educational Resources Information Center

    Matlock, Ki Lynn

    2013-01-01

    When test forms that have equal total test difficulty and number of items vary in difficulty and length within sub-content areas, an examinee's estimated score may vary across equivalent forms, depending on how well his or her true ability in each sub-content area aligns with the difficulty of items and number of items within these areas.…

  7. Assessing the Multidimensionality of a Unidimensional Scale: The Problems and Potential of the Need for Closure Scale for Educational Research.

    ERIC Educational Resources Information Center

    Crowson, H. Michael

    The dispositional motivation of individuals to engage in information processing was studied through an instrument, the Need for Closure Scale (NFCS) (A. Kruglanski and others, 1996), developed to measure differences in the need for structure and closure. One goal of the two studies reported was to address criticisms related to the dimensionality…

  8. The Confounding Effects of Ability, Item Difficulty, and Content Balance within Multiple Dimensions on the Estimation of Unidimensional Thetas

    ERIC Educational Resources Information Center

    Matlock, Ki Lynn

    2013-01-01

    When test forms that have equal total test difficulty and number of items vary in difficulty and length within sub-content areas, an examinee's estimated score may vary across equivalent forms, depending on how well his or her true ability in each sub-content area aligns with the difficulty of items and number of items within these areas.…

  9. A Q3 Statistic for Unfolding Item Response Theory Models: Assessment of Unidimensionality with Two Factors and Simple Structure

    ERIC Educational Resources Information Center

    Habing, Brian; Finch, Holmes; Roberts, James S.

    2005-01-01

    Although there are many methods available for dimensionality assessment for items with monotone item response functions, there are few methods available for unfolding item response theory models. In this study, a modification of Yen's Q3 statistic is proposed for the case of these nonmonotone item response models. Through a simulation study, the…

  10. A Comparison of Item Parameter Standard Error Estimation Procedures for Unidimensional and Multidimensional Item Response Theory Modeling

    ERIC Educational Resources Information Center

    Paek, Insu; Cai, Li

    2014-01-01

    The present study was motivated by the recognition that standard errors (SEs) of item response theory (IRT) model parameters are often of immediate interest to practitioners and that there is currently a lack of comparative research on different SE (or error variance-covariance matrix) estimation procedures. The present study investigated item…

  11. Menopausal Sexual Interest Questionnaire (MSIQ): a unidimensional scale for the assessment of sexual interest in postmenopausal women.

    PubMed

    Rosen, Raymond C; Lobo, Rogerio A; Block, Barbara A; Yang, Hwa-Ming; Zipfel, Lisa M

    2004-01-01

    A panel of experts formulated relevant domains of sexual function with a focus on sexual interest and desire. The resulting 10-item scale, the Menopausal Sexual Interest Questionnaire (MSIQ), was examined for reliability (internal consistency and test-retest repeatability), construct validity (concurrent, convergent, and discriminant), sensitivity, and specificity in a clinical trial. A principal components analysis identified three factors (desire, responsiveness, and satisfaction) with eigenvalues > 1. A high degree of internal consistency was observed for each of the three domains. Test-retest repeatability correlation coefficients for domain scores were all highly significant. The MSIQ demonstrated adequate construct validity, with all three domains showing a high degree of sensitivity and with two of the three exhibiting specificity to the effects of treatment.

  12. Not All Same-Different Discriminations Are Created Equal: Evidence Contrary to a Unidimensional Account of Same-Different Learning

    ERIC Educational Resources Information Center

    Gibson, Brett M.; Wasserman, Edward A.; Cook, Robert G.

    2006-01-01

    In Experiment 1, we trained four pigeons to concurrently discriminate displays of 16 same icons (16S) from displays of 16 different icons (16D) as well as between displays of same icons (16S) from displays that contained 15 same icons and one different icon (15S:1D). The birds rapidly learned to discriminate 16S vs. 16D displays, but they failed…

  13. A Q3 Statistic for Unfolding Item Response Theory Models: Assessment of Unidimensionality with Two Factors and Simple Structure

    ERIC Educational Resources Information Center

    Habing, Brian; Finch, Holmes; Roberts, James S.

    2005-01-01

    Although there are many methods available for dimensionality assessment for items with monotone item response functions, there are few methods available for unfolding item response theory models. In this study, a modification of Yen's Q3 statistic is proposed for the case of these nonmonotone item response models. Through a simulation study, the…

  14. A Comparison of Unidimensional and Three-Dimensional Differential Item Functioning Analysis Using Two-Dimensional Data

    ERIC Educational Resources Information Center

    Snow, Teresa K.; Oshima, T. C.

    2009-01-01

    Oshima, Raju, and Flowers demonstrated the use of an item response theory-based technique for analyzing differential item function (DIF) and differential test function for dichotomously scored data that are intended to be multidimensional. Their study assumed that the number of intended-to-be measured dimensions was correctly identified. In…

  15. Not All Same-Different Discriminations Are Created Equal: Evidence Contrary to a Unidimensional Account of Same-Different Learning

    ERIC Educational Resources Information Center

    Gibson, Brett M.; Wasserman, Edward A.; Cook, Robert G.

    2006-01-01

    In Experiment 1, we trained four pigeons to concurrently discriminate displays of 16 same icons (16S) from displays of 16 different icons (16D) as well as between displays of same icons (16S) from displays that contained 15 same icons and one different icon (15S:1D). The birds rapidly learned to discriminate 16S vs. 16D displays, but they failed…

  16. A Comparison of Item Parameter Standard Error Estimation Procedures for Unidimensional and Multidimensional Item Response Theory Modeling

    ERIC Educational Resources Information Center

    Paek, Insu; Cai, Li

    2014-01-01

    The present study was motivated by the recognition that standard errors (SEs) of item response theory (IRT) model parameters are often of immediate interest to practitioners and that there is currently a lack of comparative research on different SE (or error variance-covariance matrix) estimation procedures. The present study investigated item…

  17. Rede und Gesinnung (Speech and Ways of Thinking)

    ERIC Educational Resources Information Center

    Kienzle, Bertram

    1974-01-01

    Analyzes some of the basic ideas in Georg Franklin's book "Versuch einer neuen Lehre von den vornehmsten Gegenstanden der deutschen Sprachlehre; nach den Regeln der Vernunftlehre in sechs Abhandlungen verfasst" (1778) and compares them to those of such modern linguists and philosophers a s Searle, Austin and Wunderlich. Concludes that…

  18. Rede und Gesinnung (Speech and Ways of Thinking)

    ERIC Educational Resources Information Center

    Kienzle, Bertram

    1974-01-01

    Analyzes some of the basic ideas in Georg Franklin's book "Versuch einer neuen Lehre von den vornehmsten Gegenstanden der deutschen Sprachlehre; nach den Regeln der Vernunftlehre in sechs Abhandlungen verfasst" (1778) and compares them to those of such modern linguists and philosophers a s Searle, Austin and Wunderlich. Concludes that…

  19. Reciprocal effects between academic self-concept, self-esteem, achievement, and attainment over seven adolescent years: unidimensional and multidimensional perspectives of self-concept.

    PubMed

    Marsh, Herbert W; O'Mara, Alison

    2008-04-01

    In their influential review, Baumeister, Campbell, Krueger, and Vohs (2003) concluded that self-esteem--the global component of self-concept--has no effect on subsequent academic performance. In contrast, Marsh and Craven's (2006) review of reciprocal effects models from an explicitly multidimensional perspective demonstrated that academic self-concept and achievement are both a cause and an effect of each other. Ironically, both reviews cited classic Youth in Transition studies in support of their respective claims. In definitive tests of these counter claims, the authors reanalyze these data-including self-esteem (emphasized by Baumeister et al.), academic self-concept (emphasized by Marsh & Craven), and postsecondary educational attainment-using stronger statistical methods based on five waves of data (grade 10 through 5 years after graduation; N=2,213). Integrating apparently discrepant findings under a common theoretical framework based on a multidimensional perspective, academic self-concept had consistent reciprocal effects with both achievement and educational attainment, whereas self-esteem had almost none.

  20. Understanding the Psychopathic Personality Inventory (PPI) in terms of the unidimensionality, orthogonality, and construct validity of PPI-I and -II.

    PubMed

    Neumann, Craig S; Uzieblo, Katarzyna; Crombez, Geert; Hare, Robert D

    2013-01-01

    Comments on an article by Marcus et al. (see record 2011-23134-001). Marcus et al. (this issue) hold that PPI-I and PPI-II are generally orthogonal (uncorrelated). Examination of the primary PPI scales calls this into question. Specifically, the scales that make up Psychopathic Personality Inventory (PPI)-I and PPI-II are differentially correlated in offenders (Neumann et al., 2008) and college students (as reported in Lilienfeld, 1990, final sample). This pattern of correlations indicates that the socalled orthogonal association between PPI-I and PPI-II may be attributable to a statistical "washout" effect, rather than zero correlations across scales. The scales that make up PPI-I and PPI-II may also be correlated differentially with external correlates, rendering interpretation of PPI-I and PPI-II associations with such correlates ambiguous. The overlap of PPI scale scores among forensic and nonforensic samples also is problematic, particularly for the PPI-I scales.

  1. Assessing the Unidimensionality of the School and College Ability Test (SCAT, Spanish Version) Using Non-Parametric Methods Based on Item Response Theory

    ERIC Educational Resources Information Center

    Touron, Javier; Lizasoain, Luis; Joaristi, Luis

    2012-01-01

    The aim of this work is to analyze the dimensional structure of the Spanish version of the School and College Ability Test, employed in the process for the identification of students with high intellectual abilities. This test measures verbal and mathematical (or quantitative) abilities at three levels of difficulty: elementary (3rd, 4th, and 5th…

  2. Literacy as a Unidimensional Multilevel Construct: Validation, Sources of Influence, and Implications in a Longitudinal Study in Grades 1 to 4

    ERIC Educational Resources Information Center

    Mehta, Paras D.; Foorman, Barbara R.; Branum-Martin, Lee; Taylor, W. Patrick

    2005-01-01

    This study examined the extent to which literacy is a unitary construct, the differences between literacy and general language competence, and the relative roles of teachers and students in predicting literacy outcomes. Much of past research failed to make a distinction between variability in outcomes for individual students and variability for…

  3. How Unidimensional Are Tests Comprising Both Multiple-Choice and Free-Response Items? An Analysis of Two Tests. Program Statistics Research Technical Report No. 93-32.

    ERIC Educational Resources Information Center

    Wainer, Howard; And Others

    The relationship between the multiple-choice and free-response sections of the Computer Science and Chemistry tests of the College Board's Advanced Placement program was studied. Confirmatory factor analysis showed that the free-response sections measure the same underlying proficiency as the multiple-choice sections for the most part. However,…

  4. Assessing the Unidimensionality of the School and College Ability Test (SCAT, Spanish Version) Using Non-Parametric Methods Based on Item Response Theory

    ERIC Educational Resources Information Center

    Touron, Javier; Lizasoain, Luis; Joaristi, Luis

    2012-01-01

    The aim of this work is to analyze the dimensional structure of the Spanish version of the School and College Ability Test, employed in the process for the identification of students with high intellectual abilities. This test measures verbal and mathematical (or quantitative) abilities at three levels of difficulty: elementary (3rd, 4th, and 5th…

  5. First-passage-time statistics of a Brownian particle driven by an arbitrary unidimensional potential with a superimposed exponential time-dependent drift

    NASA Astrophysics Data System (ADS)

    Urdapilleta, Eugenio

    2015-12-01

    In one-dimensional systems, the dynamics of a Brownian particle are governed by the force derived from a potential as well as by diffusion properties. In this work, we obtain the first-passage-time statistics of a Brownian particle driven by an arbitrary potential with an exponential temporally decaying superimposed field up to a prescribed threshold. The general system analyzed here describes the sub-threshold signal integration of integrate-and-fire neuron models, of any kind, supplemented by an adaptation-like current, whereas the first-passage-time corresponds to the declaration of a spike. Following our previous studies, we base our analysis on the backward Fokker-Planck equation and study the survival probability and the first-passage-time density function in the space of the initial condition. By proposing a series solution we obtain a system of recurrence equations, which given the specific structure of the exponential time-dependent drift, easily admit a simpler Laplace representation. Naturally, the present general derivation agrees with the explicit solution we found previously for the Wiener process in (2012 J. Phys. A: Math. Theor. 45 185001). However, to demonstrate the generality of the approach, we further explicitly evaluate the first-passage-time statistics of the underlying Ornstein-Uhlenbeck process. To test the validity of the series solution, we extensively compare theoretical expressions with the data obtained from numerical simulations in different regimes. As shown, agreement is precise whenever the series is truncated at an appropriate order. Beyond the fact that both the Wiener and Ornstein-Uhlenbeck processes have a direct interpretation in the context of neuronal models, given their ubiquity in different fields, our present results will be of interest in other settings where an additive state-independent temporal relaxation process is being developed as the particle diffuses.

  6. Astronomical Perception of the Secondary School's Students in São Paulo's State School in Suzano City. (Spanish Title: Percepción Astronómica de Alumnos de la Enseñanza Media de la Red Estatal de San Pablo en la Ciudad de Suzano.) Percepção Astronômica de um Grupo de Alunos do Ensino Médio da Rede Estadual de São Paulo da Cidade de Suzano

    NASA Astrophysics Data System (ADS)

    França de Oliveira, Edilene; Voelzke, Marcos Rincon; Amaral, Luis Henrique

    2007-12-01

    año y 20,6% tenían la idea de cuales son los objetos celestes más cercanos de la Tierra. En contraposición, 67,6% clasificaron correctamente el Sol como una estrella; 55,9% relacionaron el Big Bang al origen del Universo; solamente 20,6% identificaron un año-luz como unidad de distancia y 32,4% reconocieron una estrella fugaz como meteoro. El presente análisis fue expandido para otros grupos de la Enseñanza Media, no solamente del período nocturno, sino también diurno de la misma escuela. En esta primera fase se nota el pequeño conocimiento de los alumnos sobre eventos astronómicos y principalmente la gran confusión sobre el significado correcto de los términos astronómicos populares. Embora a Astronomia seja uma das ciências mais antigas da humanidade e muitos dos conceitos astronômicos serem populares, observa-se que uma parcela significativa dos estudantes encontra-se à margem dessas informações. O presente trabalho visa analisar o nível de conhecimento básico dos alunos do Ensino Médio da Rede Estadual da cidade de Suzano quanto aos fenômenos astronômicos que os rodeiam. Para tanto foi elaborado um formulário constando de questões de múltipla escolha, aplicado no primeiro ano noturno da Escola Estadual Batista Renzi. Num espaço amostral de 34 alunos constatou-se que apenas 29,4% compreendiam a sucessão dos dias; 20,6% explicaram corretamente as estações do ano e 20,6% tinham idéia de quais são os objetos celestes mais próximos da Terra. Em contraposição, 67,6% classificaram corretamente o Sol como estrela; 55,9% relacionaram o Big Bang à origem do Universo; apenas 20,6% identificaram um ano-luz como unidade de distância e 32,4% reconheceram uma estrela cadente como meteoro. A presente análise foi expandida para mais 310 alunos de outras classes de Ensino Médio, não somente do período noturno, mas também diurno da mesma escola. Nesta primeira fase nota-se o pequeno discernimento dos alunos sobre eventos astronômicos e

  7. Nuevas tecnicas basadas en redes neuronales para el diseno de filtros de microondas multicapa apantallados

    NASA Astrophysics Data System (ADS)

    Pascual Garcia, Juan

    In this PhD thesis one method of shielded multilayer circuit neural network based analysis has been developed. One of the most successful analysis procedures of these kind of structures is the Integral Equation technique (IE) solved by the Method of Moments (MoM). In order to solve the IE, in the version which uses the media relevant potentials, it is necessary to have a formulation of the Green's functions associated to the mentioned potentials. The main computational burden in the IE resolution lies on the numerical evaluation of the Green's functions. In this work, the circuit analysis has been drastically accelerated thanks to the approximation of the Green's functions by means of neural networks. Once trained, the neural networks substitute the Green's functions in the IE. Two different types of neural networks have been used: the Radial basis function neural networks (RBFNN) and the Chebyshev neural networks. Thanks mainly to two distinct operations the correct approximation of the Green's functions has been possible. On the one hand, a very effective input space division has been developed. On the other hand, the elimination of the singularity makes feasible the approximation of slow variation functions. Two different singularity elimination strategies have been developed. The first one is based on the multiplication by the source-observation points distance (rho). The second one outperforms the first one. It consists of the extraction of two layers of spatial images from the whole summation of images. With regard to the Chebyshev neural networks, the OLS training algorithm has been applied in a novel fashion. This method allows the optimum design in this kind of neural networks. In this way, the performance of these neural networks outperforms greatly the RBFNNs one. In both networks, the time gain reached makes the neural method profitable. The time invested in the input space division and in the neural training is negligible with only few circuit analysis. To show, in a practical way, the ability of the neural based analysis method, two new design procedures have been developed. The first method uses the Genetic Algorithms to optimize an initial filter which does not fulfill the established specifications. A new fitness function, specially well suited to design filters, has been defined in order to assure the correct convergence of the optimization process. This new function measures the fulfillment of the specifications and it also prevents the appearance of the premature convergence problem. The second method is found on the approximation, by means of neural networks, of the relations between the electrical parameters, which defined the circuit response, and the physical dimensions that synthesize the aforementioned parameters. The neural networks trained with these data can be used in the design of many circuits in a given structure. Both methods had been show their ability in the design of practical filters.

  8. Actividad funcional cerebral en estado de reposo: REDES EN CONEXIÓN

    PubMed Central

    Proal, Erika; Alvarez-Segura, Mar; de la Iglesia-Vayá, Maria; Martí-Bonmatí, Luis; Castellanos, F. Xavier

    2015-01-01

    Resumen El análisis de la conectividad funcional mediante resonancia magnética funcional (RMf) puede llevarse a cabo durante la realización de una tarea, la percepción de un estímulo o en estado de reposo. Estos análisis han demostrado su fiabilidad y reproducibilidad con diferentes enfoques (matemáticos, estadísticos, físicos) para seleccionar los vóxeles activados. El estudio de la señal de baja frecuencia en la actividad cerebral a través del contraste BOLD en estado de reposo ha revelado patrones de actividad cortical sincronizados, permitiendo describir la arquitectura funcional intrínseca del cerebro humano. La comunidad científica internacional dispone de recursos compartidos que contribuirán mediante este análisis de RMf en estado de reposo a la obtención de diagnósticos y tratamientos más precisos y avanzados en el campo de las neurociencias. PMID:21365601

  9. Innovation and communicative action: health management networks and technologies.

    PubMed

    Rivera, Francisco Javier Uribe; Artmann, Elizabeth

    2016-11-03

    This article discusses elements of a theory of innovation from the perspective of innovation networks and social construction of technology, based on Habermas' Theory of Communicative Action and authors from the Sociology of Innovation. Based on the theoretical framework of the communicative production of scientific facts, we focus on innovation management as a basic dimension that must meet some organizational and methodological requirements in order to power its results. We present and discuss instruments such as Situational Planning, Prospective Analysis, Strategic Portfolio Management, and Networks Management that can help deal with the challenge of innovation and exploration of the future. We conclude that network organizational formats centered on reflexivity of interdisciplinary groups and planning approaches that encourage innovation criteria in assessing the attractiveness of activities and that help anticipate forms of innovation through systematic prospective analysis can potentiate the process of generating innovation as a product of networks. Resumo: No artigo são discutidos elementos de uma teoria da inovação numa perspectiva de redes de inovação e de construção social da tecnologia, a partir da Teoria do Agir Comunicativo de Habermas e de autores da Sociologia da Inovação. Com base no marco teórico da produção comunicativa de fatos científicos, focamos a gestão da inovação como uma dimensão fundamental que deve contemplar alguns requisitos, tanto de natureza organizacional quanto metodológica, para potencializar seus resultados. Apresentamos e discutimos instrumentos como o Planejamento Situacional, a Análise Prospectiva, a Gestão Estratégica de Portfólios e a Gestão de Redes que podem contribuir para o desafio da inovação e exploração do futuro. Conclui-se que formas organizativas em rede, centradas na reflexividade de grupos interdisciplinares, e enfoques de planejamento que estimulem o uso de critérios de inovação na

  10. Utilization of nuclear structural proteins for targeted therapy and detection of proliferative and differentiation disorders

    DOEpatents

    Lelievre, Sophie; Bissell, Mina

    2001-01-01

    The localization of nuclear apparatus proteins (NUMA) is used to identify tumor cells and different stages in the tumor progression and differentiation processes. There is a characteristic organization of NuMA in tumor cells and in phenotypically normal cells. NuMA distribution patterns are significantly less diffuse in proliferating non-malignant cells compared to malignant cells. The technique encompasses cell immunostaining using a NuMA specific antibody, and microscopic analysis of NuMA distribution within each nucleus.

  11. The Moon Phases in a Paper Box. (Spanish Title: Las Fases de la Luna en Una Caja de Cartón.) As Fases da Lua Numa Caixa de Papelão

    NASA Astrophysics Data System (ADS)

    de Fátima O. Saraiva, Maria; Amador, Cláudio B.; Kemper, Érico; Goulart, Paulo; Muller, Angela

    2007-12-01

    We present a very simple concrete model to demonstrate the concept of phases of an illuminated body. The main objective of our model is to help the understanding of the Moon phases as viewed from the perspective of an observer on Earth. The material allows the visualization of two important effects: (1st) even though all the time half Moon is illuminated by the Sun, we see different fractions of the illuminated Moon surface, depending on our angle of sight; (2nd) the orientation of the convex part of the Moon in the crescent and waning phases on the sky also depends on our perspective from Earth. The use of a closed box allows one to see the contrast among the different phases with no need of a dark room. We also present a text on the Moon phases, emphasizing the dependence of the aspect of the bright part on the angle of sight. En este trabajo proponemos la construcción de material didáctico de bajo costo para demostración del concepto de fases de un cuerpo iluminado. El principal objetivo de nuestro material es facilitar la comprensión de las fases de la Luna desde la perspectiva de un observador en la Tierra. El material ayuda la visualización de dos efectos importantes: (1º) a pesar de tener siempre la mitad de la Luna (representada por una bolita de espuma plástica o de ping-pong), iluminada por el Sol ( representado por una fuente de luz natural o artificial), vemos diferentes fracciones de su superficie iluminada, dependiendo del ángulo por el cual la vemos; (2º) la orientación del borde convexo de la Luna en las fases Creciente y Menguante también depende de la perspectiva por la cual la miramos desde la Tierra. El uso de una caja cerrada permite observar el contraste entre las diferentes fases sin necesidad de estar en un recinto oscuro. Presentamos también un texto explicativo sobre las fases de la Luna, enfatizando la dependencia de la apariencia de la parte iluminada con el ángulo de visión. Neste trabalho propomos a construção de material didático de baixo custo para demonstração do conceito de fases de um corpo iluminado. O principal objetivo de nosso material é facilitar a compreensão das fases da Lua da perspectiva de um observador na Terra. O material ajuda na visualização de dois efeitos importantes: (1º) mesmo tendo sempre a metade da "Lua" (representada por uma bolinha de isopor ou de ping-pong) iluminada pelo "Sol" (representado por uma fonte de luz natural ou artificial), nós vemos diferentes frações de sua superfície iluminada, dependendo do ângulo pelo qual a olhamos; (2º) a orientação da borda convexa da Lua nas fases Crescente e Minguante também depende da perspectiva pela qual a olhamos da Terra. O uso de uma caixa fechada permite observar o contraste entre as diferentes fases sem necessidade de estar em uma sala escurecida. Apresentamos também um texto explicativo sobre fases da Lua, enfatizando a dependência da aparência da parte iluminada com o ângulo de visada.

  12. Assessing the Dimensionality of NAEP Reading Data.

    ERIC Educational Resources Information Center

    Zwick, Rebecca

    1987-01-01

    National Assessment of Educational Progress reading data were scaled using a unidimensional item response theory model. Bock's full-information factor analysis and Rosenbaum's test of unidimensionality were applied. Conclusions about unidimensionality for balanced incomplete block spiralled data were the same as for complete data. (Author/GDC)

  13. Assessing Dimensionality of a Set of Item Responses--Comparison of Different Approaches.

    ERIC Educational Resources Information Center

    Nandakumar, Ratna

    1994-01-01

    Using simulated and real data, this study compares the performance of three methodologies for assessing unidimensionality: (1) DIMTEST; (2) the approach of Holland and Rosenbaum; and (3) nonlinear factor analysis. All three models correctly confirm unidimensionality, but they differ in their ability to detect the lack of unidimensionality.…

  14. Hacia la predicción del Número R de Wolf de manchas solares utilizando Redes Neuronales con retardos temporales

    NASA Astrophysics Data System (ADS)

    Francile, C.; Luoni, M. L.

    We present a prediction of the time series of the Wolf number R of sunspots using "time lagged feed forward neural networks". We use two types of networks: the focused and distributed ones which were trained with the back propagation of errors algorithm and the temporal back propagation algorithm respectively. As inputs to neural networks we use the time series of the number R averaged annually and monthly with the method IR5. As data sets for training and test we choose certain intervals of the time series similar to other works, in order to compare the results. Finally we discuss the topology of the networks used, the number of delays used, the number of neurons per layer, the number of hidden layers and the results in the prediction of the series between one and six steps ahead. FULL TEXT IN SPANISH

  15. Actividad solar del ciclo 23. Predicción del máximo y fase decreciente utilizando redes neuronales

    NASA Astrophysics Data System (ADS)

    Parodi, M. A.; Ceccatto, H. A.; Piacentini, R. D.; García, P. J.

    Different methods have been proposed in order to predict the maximum amplitude of solar cycles, either as a consequence of the intrinsic importance of this event and because of its relation with solar storms and possible effects upon satellites, communication systems, etc. In this work, a neural network solar activity prediction is presented, measured through the sunspot number (SSN). The 16-units neural network, with a 12:3:1 architecture, was trained in a ``feed-forward" propagation way and learning by the so called ``back propagation rule". The annual mean SSN data in the 1700-1975 and 1987-1998 periods were used as the training set. The solar cycle 21 (1976-1986) was taken as the cross-validation data set. After performing the network training we obtained a prediction of the maximum annual mean for the current solar cycle 23, SSNmax= 135 ±17 at the year 2000, which is 13% smaller than the International Consensus Commitee's mean maximum prediction obtained through ``precursor techniques". On the other hand, our prediction is only about 4% smaller than the Consensus's neural network mean prediction. A ``multiple step" prediction technique was also performed and SSN annual mean predicted values for the near-maximum (from the present year 1999 to beyond the maximum) and the declining activity of solar cycle 23 are presented in this work. The sensibility of predictions is also tested. To do so, we changed the interval width and comparated our results with those of a previous neural network prediction and those of others authors using differents methods.

  16. Regional Emissions Data Base and Evaluation System (REDES): Volume 3, Environmental profiles of selected clean coal technologies

    SciTech Connect

    Poch, L.A.; Gillette, J.L.; Boyd, G.A.

    1988-06-01

    The clean coal technologies described in this report make use of advanced combustors, alternative fuels, coal preparation processes, fluidized-bed combustors, flue-gas cleanup technologies, coal liquefaction processes, and surface gasification. Each profile begins with a brief description of the technology, followed by an assessment of its applicability to the utility or industrial sector in terms of fuel sulfur content, boiler size, and boiler market (new, repower, and/or retrofit). The sulfur content of the coal is described as being low, medium, or high. Low-sulfur coal contains less than 1.5% sulfur, medium-sulfur coal has 1.5--3% sulfur, and high-sulfur coal contains greater than 3% sulfur. Boiler size (or unit output of electricity) is discussed in terms of being small, medium, or large. A small boiler has less than 100 MW output, a medium boiler has 100--400 MW output, and a large boiler has greater than 400 MW output. Removal efficiencies or emission levels for sulfur dioxide (SO/sub 2/), oxides of nitrogen (NO/sub x/), and particulates are described, as are the anticipated changes in heat rate that would result from the use of each technology. The wastes generated by each technology are also discussed. Following each technology's profile is a bibliography that lists the sources used to compile the values for the various parameters. 49 refs.

  17. Extracción de conocimiento en bases de datos astronómicas mediante redes de neuronas artificiales: aplicaciones en la misión Gaia

    NASA Astrophysics Data System (ADS)

    Fustes Villadóniga, Diego

    2014-02-01

    In the so-called IT era, the capabilities of data acquisition systems have increased to such an extent that it has become difficult to store all the information they produce, and analyse it. This explosion of data has recently appeared in the field of Astronomy, where an increasing number of objects are being observed on a regular basis. An example of this is the upcoming Gaia mission, which will pick up multiple properties of a billion stars, whose information will have a volume of approximately a petabyte. The analysis of a similar amount of information inevitably requires the development of new data analysis methods to extract all the knowledge it contains. This thesis is devoted to the development of data analysis methods to be integrated in the Gaia pipeline, such that knowledge can be extracted from the data collected by the mission. In order to analyze the data from the Gaia mission, the European Space Agency organized the Data Processing and Analysis Consortium (DPAC) which is composed of hundreds of scientists and engineers. DPAC is divided into eight Coordination Units (CUs). This thesis is dedicated to algorithm development in CU8, which is responsible for source classification and astrophysical parameters (AP) estimation. Methods based on Artificial Neural Networks (ANNs) are developed to perform the tasks related to two different work packages in CU8: the GSP-Spec package (GWP-823), and the OA package (GWP-836). The GSP-Spec package is responsible for estimating stellar APs by means of the Radial Velocity Spectrograph (RVS) spectrum. This work presents the development of one of the GSP-Spec modules, which is based on the application of feed-forward ANNs. A methodology is described, based on the optimization of genetic algorithms and aimed at obtaining an optimal set of configuration parameters for the ANN in each case, depending on the signal to noise ratio (SNR) in the RVS spectrum and on the type of star to parameterize. Furthermore, in order to improve the AP estimates, wavelet signal processing techniques, applied to the RVS spectrum, are studied. Despite the effectiveness shown by ANNs in estimating APs, in principle they lack the ability to provide an uncertainty value on these estimates, making it impossible to determine their reliability. Because of this, a new architecture for the ANN is presented in which the inputs and outputs are reversed, so that the ANN estimates the RVS spectrum from the APs. Such an architecture is called Generative ANN (GANN) and is applied to the AP estimation of a set of simulated RVS spectra for the Gaia mission, where it is more effective than the conventional ANN model, in the case of faint stars with low SNR. Finally, the GANN can be applied for obtaining the posterior probability of each of the APs according to the RVS spectrum, allowing for their more complete analysis. Given the nature of the Gaia mission, which is the first astronomical mission that will observe, in an unbiased way, the entire sky up to magnitude 20, a large number of outliers are expected. The OA package in CU8 handles the processing of this type of objects, which are defined as those that could not be reliably classified by the methods in the upstream classification packages. OA methods are based on the unsupervised learning of all outliers. Such learning has two parts: clustering and dimensionality reduction. The Self-Organizing Map (SOM) algorithm is selected as a basis for this learning. Its effectiveness is demonstrated when it is applied, with an optimal configuration, to the Gaia simulations. Furthermore, the algorithm is applied to real outliers from the SDSS catalog. Since a subsequent identification of the clusters obtained by the SOM is necessary, two different methods of identification are applied. The first method is based on the similarity between the SOM prototypes and the Gaia simulations, and the second method is based on the recovery of stored classifications in the SIMBAD catalog by cross-matching celestial coordinates. Thanks to the visualization of the SOM planes, and to both methods of identification, it is possible to distinguish between valid observations and observational artifacts. Furthermore, the method allows for the selection of objects of interest for follow-up observations, in order to determine their nature.

  18. Pragma- und textilinguistische Untersuchungsmethoden zur indirekten Rede im Englischen (Pragmatic and Text-Linguistic Research Methods on Indirect Discourse in English)

    ERIC Educational Resources Information Center

    Ziegesar, Detlef von

    1976-01-01

    Examines the mechanisms involved in changing from direct to indirect discourse, taking as a starting point research findings in linguistic pragmatics, which involve the practical application of speech symbol use between speaker and hearer. (Text is in German.) (IFS/WGA)

  19. Textlinguistik und Schulunterricht. Am Beispiel der Behandlung der indirekten Rede im Englischen. (Text Linguistics and Instruction in the Schools: Example: The Treatment of Indirect Discourse in English).

    ERIC Educational Resources Information Center

    Kueper, Christoph

    1979-01-01

    Compares sentence grammar with text linguistics, giving a survey of the treatment of indirect discourse in school grammars, and finding them inadequate. Recommends rules derived from text linguistics in spite of their greater complexity, because they do not hold the student to mechanical recasting of sentences. (IFS/WGA)

  20. Die Indirekte Rede als Diskursstrategie: Innovative Lehrmethoden zum Konjunktiv I (Indirect Speech as a Discourse Strategy: Innovative Teaching Methods for the Subjunctive).

    ERIC Educational Resources Information Center

    Gramberg, Anne-Kathrin; Heinze, Karin U.

    1993-01-01

    This article talks about the subjunctive of indirect speech, in which its important functions and meanings are depicted. An analysis of the instructional materials used in the first and second years of language study, followed by practical curriculum recommendations, demonstrates how this grammatical phenomenon can be established in an advanced…

  1. Textlinguistik und Schulunterricht. Am Beispiel der Behandlung der indirekten Rede im Englischen. (Text Linguistics and Instruction in the Schools: Example: The Treatment of Indirect Discourse in English).

    ERIC Educational Resources Information Center

    Kueper, Christoph

    1979-01-01

    Compares sentence grammar with text linguistics, giving a survey of the treatment of indirect discourse in school grammars, and finding them inadequate. Recommends rules derived from text linguistics in spite of their greater complexity, because they do not hold the student to mechanical recasting of sentences. (IFS/WGA)

  2. Die Indirekte Rede als Diskursstrategie: Innovative Lehrmethoden zum Konjunktiv I (Indirect Speech as a Discourse Strategy: Innovative Teaching Methods for the Subjunctive).

    ERIC Educational Resources Information Center

    Gramberg, Anne-Kathrin; Heinze, Karin U.

    1993-01-01

    This article talks about the subjunctive of indirect speech, in which its important functions and meanings are depicted. An analysis of the instructional materials used in the first and second years of language study, followed by practical curriculum recommendations, demonstrates how this grammatical phenomenon can be established in an advanced…

  3. Pragma- und textilinguistische Untersuchungsmethoden zur indirekten Rede im Englischen (Pragmatic and Text-Linguistic Research Methods on Indirect Discourse in English)

    ERIC Educational Resources Information Center

    Ziegesar, Detlef von

    1976-01-01

    Examines the mechanisms involved in changing from direct to indirect discourse, taking as a starting point research findings in linguistic pragmatics, which involve the practical application of speech symbol use between speaker and hearer. (Text is in German.) (IFS/WGA)

  4. Projective Item Response Model for Test-Independent Measurement

    ERIC Educational Resources Information Center

    Ip, Edward Hak-Sing; Chen, Shyh-Huei

    2012-01-01

    The problem of fitting unidimensional item-response models to potentially multidimensional data has been extensively studied. The focus of this article is on response data that contains a major dimension of interest but that may also contain minor nuisance dimensions. Because fitting a unidimensional model to multidimensional data results in…

  5. A Note on the Dimensionality of Quality of Life Scales: An Illustration with the Satisfaction with Life Scale (SWLS)

    ERIC Educational Resources Information Center

    Slocum-Gori, Suzanne L.; Zumbo, Bruno D.; Michalos, Alex C.; Diener, Ed

    2009-01-01

    A case is made that measures used in quality of life and happiness research will be essentially unidimensional: inherently tapping minor dimensions. This is illustrated using Diener's Satisfaction with Life Scale (SWLS). It is shown that the SWLS does not meet the standard of strict unidimensionality, but that the interpretation of the total scale…

  6. An Examination of the Effect of Multidimensionality on Parallel Forms Construction.

    ERIC Educational Resources Information Center

    Ackerman, Terry A.

    This paper examines the effect of using unidimensional item response theory (IRT) item parameter estimates of multidimensional items to create weakly parallel test forms using target information curves. To date, all computer-based algorithms that have been devised to create parallel test forms assume that the items are unidimensional. This paper…

  7. Formulation of a DIMTEST Effect Size Measure (DESM) and Evaluation of the DESM Estimator Bias

    ERIC Educational Resources Information Center

    Seo, Minhee; Roussos, Louis A.

    2010-01-01

    DIMTEST is a widely used and studied method for testing the hypothesis of test unidimensionality as represented by local item independence. However, DIMTEST does not report the amount of multidimensionality that exists in data when rejecting its null. To provide more information regarding the degree to which data depart from unidimensionality, a…

  8. Assessment of the Dimensionality of NAEP Year 15 Reading Data.

    ERIC Educational Resources Information Center

    Zwick, Rebecca

    Reading test data from the National Assessment of Educational Progress (NAEP) were scaled using the unidimensional item response theory model. Data were collected for students aged 9, 13, and 17. To determine whether the responses to the reading items were consistent with unidimensionality, four different methods were applied: (1) principal…

  9. Formulation of a DIMTEST Effect Size Measure (DESM) and Evaluation of the DESM Estimator Bias

    ERIC Educational Resources Information Center

    Seo, Minhee; Roussos, Louis A.

    2010-01-01

    DIMTEST is a widely used and studied method for testing the hypothesis of test unidimensionality as represented by local item independence. However, DIMTEST does not report the amount of multidimensionality that exists in data when rejecting its null. To provide more information regarding the degree to which data depart from unidimensionality, a…

  10. Simultaneous Estimation of Overall and Domain Abilities: A Higher-Order IRT Model Approach

    ERIC Educational Resources Information Center

    de la Torre, Jimmy; Song, Hao

    2009-01-01

    Assessments consisting of different domains (e.g., content areas, objectives) are typically multidimensional in nature but are commonly assumed to be unidimensional for estimation purposes. The different domains of these assessments are further treated as multi-unidimensional tests for the purpose of obtaining diagnostic information. However, when…

  11. Dimensionality of the Bem Sex Role Inventory: A Multidimensional Analysis.

    ERIC Educational Resources Information Center

    Ruch, Libby O.

    1984-01-01

    Replicated Pedhazur and Tetenbaum's study that raised questions about the unidimensionality of the feminine and masculine subscales of Bem Sex Role Inventory (BSRI). Factor analysis and smallest space analysis indicated that subsets are not unidimensional. However, results of factor analysis but not smallest space analysis were consistent with…

  12. One or Two Dimensions in Spontaneous Classification: A Simplicity Approach

    ERIC Educational Resources Information Center

    Pothos, Emmanuel M.; Close, James

    2008-01-01

    When participants are asked to spontaneously categorize a set of items, they typically produce unidimensional classifications, i.e., categorize the items on the basis of only one of their dimensions of variation. We examine whether it is possible to predict unidimensional vs. two-dimensional classification on the basis of the abstract stimulus…

  13. A Note on the Dimensionality of Quality of Life Scales: An Illustration with the Satisfaction with Life Scale (SWLS)

    ERIC Educational Resources Information Center

    Slocum-Gori, Suzanne L.; Zumbo, Bruno D.; Michalos, Alex C.; Diener, Ed

    2009-01-01

    A case is made that measures used in quality of life and happiness research will be essentially unidimensional: inherently tapping minor dimensions. This is illustrated using Diener's Satisfaction with Life Scale (SWLS). It is shown that the SWLS does not meet the standard of strict unidimensionality, but that the interpretation of the total scale…

  14. A Validity Study of Scores from Self-Anchored-Type Scales for Measuring Depression and Self-Esteem

    ERIC Educational Resources Information Center

    Nugent, William R.

    2004-01-01

    A study was conducted to test the hypothesis that scores from a self-anchored scale for depression function as unidimensional indicators of depression and that scores from a self-anchored scale for self-esteem function as unidimensional indicators of self-esteem. A total of 228 responses were obtained from a purposive sample of clinical and…

  15. One or Two Dimensions in Spontaneous Classification: A Simplicity Approach

    ERIC Educational Resources Information Center

    Pothos, Emmanuel M.; Close, James

    2008-01-01

    When participants are asked to spontaneously categorize a set of items, they typically produce unidimensional classifications, i.e., categorize the items on the basis of only one of their dimensions of variation. We examine whether it is possible to predict unidimensional vs. two-dimensional classification on the basis of the abstract stimulus…

  16. Developing a Common Language for Tumor Response to Immunotherapy: Immune-related Response Criteria using Unidimentional measurements

    PubMed Central

    Nishino, Mizuki; Giobbie-Hurder, Anita; Gargano, Maria; Suda, Margaret; Ramaiya, Nikhil H.; Hodi, F. Stephen

    2013-01-01

    Purpose Immune-related response criteria (irRC) was developed to adequately assess tumor response to immunotherapy. The irRC are based on bidimensional measurements, as opposed to unidimensional measurements defined by RECIST, which has been widely used in solid tumors. We aimed to compare response assessment by bidimensional versus unidimensional irRC in advanced melanoma patients treated with ipilimumab. Methods Fifty-seven patients with advanced melanoma treated with ipilimumab in a phase II, expanded access trial were studied. Bidimensional tumor measurement records prospectively performed during the trial were reviewed to generate a second set of measurements using unidimensional, longest diameter measurements. The percent changes of measurements at follow-up, best overall response, and time-to-progression (TTP) were compared between bidimensional and unidimensional irRC. Interobserver variability for bidimensional and unidimensional measurements was assessed in randomly selected 25 patients. Results The percent changes at follow-up scans were highly concordant between the two criteria (Spearman r: 0.953-0.965, 1st −4th follow-up). The best immune-related response was highly concordant between the two criteria (κw=0.881). TTP was similar between the bidmensional and unidimensional assessments (progression-free at 6 months: 70% versus 81%, respectively). The unidimensional measurements were more reproducible than bidimensional measurements, with the 95% limits of agreement of (−16.1%, 5.8%) versus (−31.3%, 19.7%), respectively. Conclusion Immune-related response criteria using the unidimensional measurements provided highly concordant response assessment compared to the bidimensional irRC, with less measurement variability. The use of unidimensional irRC is proposed to assess response to immunotherapy in solid tumors, given its simplicity, higher reproducibility and high concordance with the bidimensional irRC. PMID:23743568

  17. Experiences in the Family Health Strategy: demands and vulnerabilities in the territory.

    PubMed

    Pinto, Antonio Germane Alves; Jorge, Maria Salete Bessa; Marinho, Mirna Neyara Alexandre de Sá Barreto; Vidal, Emery Ciana Figueirêdo; Aquino, Priscila de Souza; Vidal, Eglídia Carla Figueirêdo

    2017-01-01

    To understand the daily demands of Family Health Strategy in clinical practice of the team and social vulnerabilities of community territory. Research with qualitative approach, in a critical-reflexive perspective, held with two teams of the Family Health Strategy, in the city of Fortaleza, State of Ceará, Brazil. The participants were 22 users and 19 health professionals from the basic health network. Data from the interviews and observation were analyzed under the assumptions of critical hermeneutics. We highlight the unveiling of sufferings and daily clashes, the influence of social determinants on health and psychosocial demands, limits and possibilities of everyday clinical practice. The clinic attention must recognize the perceptions and living conditions by listening and promoting health in the community. Compreender as demandas cotidianas da Estratégia Saúde da Família na prática clínica da equipe e as vulnerabilidades sociais do território comunitário. Pesquisa com abordagem qualitativa, numa perspectiva crítico-reflexiva, realizada com duas equipes da Estratégia Saúde da Família, no município de Fortaleza, Estado do Ceará, Brasil. Os participantes foram 22 usuários e 19 profissionais de saúde da rede básica de saúde. Os dados das entrevistas e observação foram analisados sob os pressupostos da hermenêutica crítica. Evidenciam-se o desvelamento de sofrimentos e enfrentamentos cotidianos, a influência dos determinantes sociais na saúde e as demandas psicossociais, limites e possibilidades da prática clínica cotidiana. Considera-se que a atenção clínica deve reconhecer as percepções e condições de vida pela escuta e ações de promoção de saúde na comunidade.

  18. Gaseous detonations

    SciTech Connect

    Nettleton, M.A.

    1987-01-01

    Focusing predominantly on safety problems in handling combustible gas or dust mixtures with air or oxygen, the book is a reference on gaseous detonations. Topics covered include: unidimensional models, structure of detonation fronts, and interaction of a detonation with confinement.

  19. An evaluation of the Organizational Learning Survey.

    PubMed

    Chakrabarty, Subhra; Rogé, Joseph N

    2002-12-01

    A mail survey of a national random sample of 2,000 marketing managers was conducted. The data provided by 221 respondents were analyzed to assess the unidimensionaliry of the 21-item 1997 Organizational Learning Survey developed by Goh and Richards. A confirmatory factor analysis using LISREL 8.30 did not support the unidimensionality of the 21-item survey; however, unidimensionality was established for most of the dimensions. Managerial implications and directions for research were suggested.

  20. Inclusion of Astronomy Themes in an Inovative Approach of Informal Physics Teaching for High School Students. (Spanish Title: Inclusión de Temas Astronómicos en Uma Abordaje Innovadora de la Enseñanza Informal de Física Para Estudiantes de Secumdaria.) Inclusão de Temas Astronômicos Numa Abordagem Inovadora do Ensino Informal de Física Para Estudantes do Ensino Médio

    NASA Astrophysics Data System (ADS)

    Tiara Mota, Aline; de Morais Bonomini, Iracema Ariel; Meloni Martins Rosado, Ricardo

    2009-12-01

    The current work reports on an experience on Astronomy education at the Federal University of Itajubá through an extra-curricular course offered for High School students. This initiative was motivated by the low attention paid to the Astronomy subjects at this stage of the Brazilian Formal Education, in spite that the National Curricular Parameters (PCN and PCN+, in Brazil) point out the importance of their inclusion Este artículo relata una experiencia en la enseñanza de la astronomía efectuada en la Universidad Federal de Itajubá en la forma de un curso de extensión orientado para los estudiantes del colegio secundario. Esta iniciativa surgió de constatar la poca atención dada a la Astronomía en esta etapa de la Educación formal brasileña, a pesar que los Parámetros Curriculares Nacionales (PCN y PCN+, en Brasil) destacan la importancia de su inclusión. Este artigo relata uma experiência em ensino de Astronomia realizada na Universidade Federal de Itajubá na forma de um curso de extensão voltado para alunos do Ensino Médio. Esta iniciativa surgiu da pouca atenção que se dá à Astronomia nesta etapa da Educação embora os Parâmetros Curriculares Nacionais (PCN e PCN+) apontem a importância de sua inclusão.

  1. Aplicación de técnicas de análisis de redes sociales y de co-ocurrencia de palabras en la determinación de frentes de investigación

    NASA Astrophysics Data System (ADS)

    Boeris, C. E.

    A bibliometric study of the scientific production of the IAR researchers has been performed, with the aim of determining the institute's research fronts and groups of researchers working on these fronts. Methods of analysis of co-occurrence of words, authorship analysis and social network analysis (SNA) has been applied by extracting keywords and the names of the authors on the base of published works. The results support the existence of two research fronts within the institution. FULL TEXT IN SPANISH

  2. Memorias Conferencia Internacional IEEE Mexico 1971, Sobre Sistemas, Redes Y Computadoras. Volumen I and Volumen II. (Proceedings of International Conference of IEEE Concerning Systems, Networks, and Computers. Volume I and Volume II.

    ERIC Educational Resources Information Center

    Concheiro, A. Alonso, Ed.; And Others

    The following papers in English from this international conference may be of particular interest to those in the field of education. T. Nakahara, A. Tsukamota, and M. Matsumoto describe a computer-aided design technique for an economical urban cable television system. W. D. Wasson and R. K. Chitkara outline a recognition scheme based on analysis…

  3. Percepção astronómica de um grupo de alunos do ensino médio de uma escola da rede estadual de São Paulo

    NASA Astrophysics Data System (ADS)

    de Oliveria, E. F.; Voelzke, M. R.

    2009-03-01

    Sendo a Astronomia uma das cièncias mais antigas da humanidade, e considerando sua importáncia histórica e cultural, é de extrema releváncia que tópicos relacionados a ela sejam tratados nas escolas. Embora os Parámetros Curriculares Nacionais do Ensino Médio (PCN-EM) e as Orientaçiacute;es Complementares aos Parámetros (PCN+) apontem a importáncia de uma abordagem significativa de conceitos relacionados à Astronomia nas aulas de Física, muitos estudantes terminam o Ensino Médio (EM) sem compreender a razão de certos acontecimentos de origem celeste, ainda que estes façam parte de seu cotidiano e sejam alvos da curiosidade natural dos jovens. Da observação dessa curiosidade em alunos de uma escola pública paulista, na cidade de Suzano, surgiu o interesse em investigar os conhecimentos básicos em Astronomia dos alunos do Ensino Médio desta escola, constituindo-se este como principal objetivo desta pesquisa. Para tanto foi elaborado um questionário de múltipla escolha aplicado inicialmente a 34 alunos do primeiro ano e, posteriormente, a mais 310, distribuídos entre as très séries do Ensino Médio dos períodos matutino e noturno. Dessa forma, observou-se que 73,9% dos estudantes identificaram o Sol como sendo uma estrela, 67,1% mostraram compreender a sucessão entre dia e noite e 52,3% relacionaram o Big Bang à origem do Universo. Em contrapartida, apenas 34,5% relacionaram as estaçíes do ano à inclinação do eixo de rotação da Terra, 21,3% indicaram a influència gravitacional simultánea da Lua e do Sol como responsável pelo fenòmeno das marés, 24,5% indicaram corretamente quais são os objetos celestes mais próximos da Terra, 36,1% identificaram ano-luz como uma medida de distáncia e 34,2% reconheceram as estrelas cadentes como meteoros, evidenciando-se assim o pequeno discernimento dos estudantes quanto aos fenòmenos e termos astronòmicos do cotidiano. Além disso, foram comparadas as respostas de alun! os de diferentes séries e períodos, observando-se, dentre ou tras coi sas, que os estudantes do terceiro ano apresentam um percentual de acertos semelhante ao dos alunos do primeiro, caracterizando que a abordagem de tópicos relacionados à astronomia no Ensino Médio não tem contribuído de forma significativa para uma maior compreensão dos fenòmenos e conceitos.

  4. Análise sobre o Conhecimento de um Grupo de Alunos do Ensino Médio da Rede Estadual de São Paulo sobre Termos e Fenômenos Astronômicos do Cotidiano

    NASA Astrophysics Data System (ADS)

    de Oliveira, E. F.; Voelzke, M. R.; Amaral, L. H.

    2007-08-01

    Embora os Parâmetros Curriculares Nacionais do Ensino Médio (PCN-EM) e as orientações complementares a esses Parâmetros (PCN+) apontem a importância de uma abordagem significativa de conceitos relacionados à astronomia nas aulas de Física, muitos estudantes terminam o Ensino Médio (EM) sem compreender a razão de certos acontecimentos de origem celeste, ainda que estes façam parte de seu cotidiano. Este trabalho tem por objetivo analisar os conhecimentos básicos em astronomia dos alunos de EM da escola estadual Batista Renzi, bem como investigar os meios através dos quais estes conhecimentos foram adquiridos. Para tanto foi elaborado um questionário de múltipla escolha aplicado a 310 alunos distribuídos entre as três séries do EM dos períodos matutino e noturno. Dessa forma, observou-se que apenas 34,5% relacionaram as estações do ano à inclinação do eixo de rotação da Terra, 21,3% indicaram a influência gravitacional da Lua e do Sol como responsáveis pelo fenômeno das marés, 24,5% indicaram corretamente quais são os objetos celestes mais próximos da Terra, 36,1% identificaram ano-luz como uma medida de distância e 34,2% reconheceram uma estrela cadente como meteoro. Em contrapartida, 67,1% compreendiam a sucessão entre dia e noite, 73,9% identificaram o Sol como estrela e 52,3% relacionaram o Big Bang à origem do Universo. Além disso, foram comparadas as respostas de alunos de diferentes séries e períodos, observando-se, dentre outras coisas, que os estudantes do terceiro ano apresentam um percentual de acertos semelhante ao dos alunos do primeiro, caracterizando que a abordagem de tópicos relacionados à astronomia no EM não tem contribuído para uma maior compreensão dos fenômenos e conceitos.

  5. Memorias Conferencia Internacional IEEE Mexico 1971, Sobre Sistemas, Redes Y Computadoras. Volumen I and Volumen II. (Proceedings of International Conference of IEEE Concerning Systems, Networks, and Computers. Volume I and Volume II.

    ERIC Educational Resources Information Center

    Concheiro, A. Alonso, Ed.; And Others

    The following papers in English from this international conference may be of particular interest to those in the field of education. T. Nakahara, A. Tsukamota, and M. Matsumoto describe a computer-aided design technique for an economical urban cable television system. W. D. Wasson and R. K. Chitkara outline a recognition scheme based on analysis…

  6. Investigating the Impact of Item Parameter Drift for Item Response Theory Models with Mixture Distributions

    PubMed Central

    Park, Yoon Soo; Lee, Young-Sun; Xing, Kuan

    2016-01-01

    This study investigates the impact of item parameter drift (IPD) on parameter and ability estimation when the underlying measurement model fits a mixture distribution, thereby violating the item invariance property of unidimensional item response theory (IRT) models. An empirical study was conducted to demonstrate the occurrence of both IPD and an underlying mixture distribution using real-world data. Twenty-one trended anchor items from the 1999, 2003, and 2007 administrations of Trends in International Mathematics and Science Study (TIMSS) were analyzed using unidimensional and mixture IRT models. TIMSS treats trended anchor items as invariant over testing administrations and uses pre-calibrated item parameters based on unidimensional IRT. However, empirical results showed evidence of two latent subgroups with IPD. Results also showed changes in the distribution of examinee ability between latent classes over the three administrations. A simulation study was conducted to examine the impact of IPD on the estimation of ability and item parameters, when data have underlying mixture distributions. Simulations used data generated from a mixture IRT model and estimated using unidimensional IRT. Results showed that data reflecting IPD using mixture IRT model led to IPD in the unidimensional IRT model. Changes in the distribution of examinee ability also affected item parameters. Moreover, drift with respect to item discrimination and distribution of examinee ability affected estimates of examinee ability. These findings demonstrate the need to caution and evaluate IPD using a mixture IRT framework to understand its effects on item parameters and examinee ability. PMID:26941699

  7. The Factor Structure of the Values in Action Inventory of Strengths (VIA-IS): An Item-Level Exploratory Structural Equation Modeling (ESEM) Bifactor Analysis.

    PubMed

    Ng, Vincent; Cao, Mengyang; Marsh, Herbert W; Tay, Louis; Seligman, Martin E P

    2016-10-13

    The factor structure of the Values in Action Inventory of Strengths (VIA-IS; Peterson & Seligman, 2004) has not been well established as a result of methodological challenges primarily attributable to a global positivity factor, item cross-loading across character strengths, and questions concerning the unidimensionality of the scales assessing character strengths. We sought to overcome these methodological challenges by applying exploratory structural equation modeling (ESEM) at the item level using a bifactor analytic approach to a large sample of 447,573 participants who completed the VIA-IS with all 240 character strengths items and a reduced set of 107 unidimensional character strength items. It was found that a 6-factor bifactor structure generally held for the reduced set of unidimensional character strength items; these dimensions were justice, temperance, courage, wisdom, transcendence, humanity, and an overarching general factor that is best described as dispositional positivity. (PsycINFO Database Record

  8. The multidimensional assessment of perfectionistic automatic thoughts: a commentary on "Examining mutual suppression effects in the assessment of perfectionism cognitions: evidence supporting multidimensional assessment".

    PubMed

    Flett, Gordon L; Hewitt, Paul L

    2014-12-01

    In the current article, we comment on a recent article by Stoeber, Kobori, and Brown that provided evidence suggesting that a multidimensional approach to perfectionistic cognitions is superior to a unidimensional approach in predicting maladjustment. They also showed with their data from a university student sample that our Perfectionism Cognitions Inventory has multiple factors in contrast to our unidimensional approach. Our commentary focuses primarily on the issue of whether the Perfectionism Cognitions Inventory should be considered unidimensional versus multidimensional and outlines concerns about how perfectionism cognition factors should be used and interpreted. Although there are serious interpretive problems inherent in existing multidimensional measures of perfectionism cognitions, it is apparent that a cognitive approach is an important and viable supplement to the extensive focus on the trait multidimensional perfectionism that is currently in vogue. We conclude by discussing the potential clinical uses of cognitive assessments of perfectionism.

  9. Further examination of the Organizational Culture Scale of Artifacts.

    PubMed

    Bonavia, Tomas; Molina, J Gabriel; Boada, Joan

    2009-12-01

    The construct validity of a 10-item scale oriented to measure traditional culture, the Organizational Culture Scale of Artifacts, was analyzed under the hypothesis of unidimensionality. Confirmatory factor analysis took into account the method effects associated with reverse-worded items. Based on the data from one-half of a sample of 926 participants (79.8% male; M age = 33.4 yr., SD = 12.8), working in different companies supported a unidimensional structure, with the elimination of two items from the scale. The resulting 8-item scale was reanalyzed, this time with the second half of the split sample. Support was found for the scale's unidimensionality with this second data set.

  10. A Multi-Study Analysis of Conceptual and Measurement Issues Related to Health Research on Acculturation in Latinos

    PubMed Central

    Andrews, Arthur R.; Bridges, Ana J.; Gomez, Debbie

    2014-01-01

    Purpose The aims of the study were to evaluate the orthogonality of acculturation for Latinos. Design Regression analyses were used to examine acculturation in two Latino samples (N = 77; N = 40). In a third study (N = 673), confirmatory factor analyses compared unidimensional and bidimensional models. Method Acculturation was assessed with the ARSMA-II (Studies 1 and 2), and language proficiency items from the Children of Immigrants Longitudinal Study (Study 3). Results In Studies 1 and 2, the bidimensional model accounted for slightly more variance (R2Study 1 = .11; R2Study 2 = .21) than the unidimensional model (R2Study 1 = .10; R2Study 2 = .19). In Study 3, the bidimensional model evidenced better fit (Akaike information criterion = 167.36) than the unidimensional model (Akaike information criterion = 1204.92). Discussion/Conclusions Acculturation is multidimensional. Implications for Practice Care providers should examine acculturation as a bidimensional construct. PMID:23361579

  11. Problem Articulation and the Processes of Assistance: An Activity Theoretic View of Mediation in Game Play

    ERIC Educational Resources Information Center

    Stone, Lynda D.; Gutierrez, Kris D.

    2007-01-01

    In this article, we study a local adaptation of the Fifth Dimension [Cole, M. (1996). "Cultural psychology: A once and future discipline." Cambridge: Cambridge University Press] known as Las Redes (i.e., Networks of Collaboration in the Fifth Dimension) to examine how the multiple activity systems of Las Redes, e.g. the undergraduate course and…

  12. Particulate Meso-scale Mechanics Diagnostics: Magnetic Sensors for Dynamic State Orientation

    DTIC Science & Technology

    2013-12-01

    Research Laboratory for giving this opportunity to work at the Eglin AFB, FL. REFERENCES 1. Brian D. Reding , “Development of Particulate Materials...Measurements," Sandia Report, 1984. 15. I.N. Tansel, B. Reding , W. L. Cooper, “Lagrangian Point State Estimation with Optimized, Redundant Induction Coil

  13. Enabling Others to Win in a Complex World: Maximizing Security Force Assistance Potential in the Regionally Aligned Brigade Combat Team

    DTIC Science & Technology

    2015-12-01

    once units rede - ployed to the United States, training focus and organi- zation completely shifted away from SFA, running the risk of failing to...the Global Response Force: Rede - fining Readiness.” Military Review (July-August 2013). French, Jeffrey W. “Fighting With One Arm Behind Our Back

  14. Problem Articulation and the Processes of Assistance: An Activity Theoretic View of Mediation in Game Play

    ERIC Educational Resources Information Center

    Stone, Lynda D.; Gutierrez, Kris D.

    2007-01-01

    In this article, we study a local adaptation of the Fifth Dimension [Cole, M. (1996). "Cultural psychology: A once and future discipline." Cambridge: Cambridge University Press] known as Las Redes (i.e., Networks of Collaboration in the Fifth Dimension) to examine how the multiple activity systems of Las Redes, e.g. the undergraduate course and…

  15. Instruction on Piagetian concepts for children with mental retardation.

    PubMed

    McCormick, P K; Campbell, J W; Pasnak, R; Perry, P

    1990-12-01

    Eighteen children with mild mental retardation were pretested on unidimensional classification (oddity), unidimensional seriation, number conservation, Slosson's Intelligence Test, and the Peabody Picture Vocabulary Test (PPVT). The children were instructed on the Piagetian concepts twice per week for 4 months via a learning-set technique. All 315 problems (except 20 verbal classification and 15 verbal seriation items) involved concrete items. When posttested at the semester's end, the children had, with few exceptions, mastered the Piagetian concepts and made significant gains on performance on the PPVT.

  16. Value-based formulas for purchasing. PEHP's designated service provider program: value-based purchasing through global fees.

    PubMed

    Emery, D W

    1997-01-01

    In many circles, managed care and capitation have become synonymous; unfortunately, the assumptions informing capitation are based on a flawed unidimensional model of risk. PEHP of Utah has rejected the unidimensional model and has therefore embraced a multidimensional model of risk that suggests that global fees are the optimal purchasing modality. A globally priced episode of care forms a natural unit of analysis that enhances purchasing clarity, allows providers to more efficiently focus on the Marginal Rate of Technical Substitution, and conforms to the multidimensional reality of risk. Most importantly, global fees simultaneously maximize patient choice and provider cost consciousness.

  17. Tissue phenotype depends on reciprocal interactions between the extracellular matrix and the structural organization of the nucleus

    SciTech Connect

    Lelie'vre, S.A.; Weaver, V.M.; Nickerson, J.A.; Larabell, C.A.; Bhaumik, A.; Petersen, O.W.; Bissell, M.J.

    1998-08-14

    What determines the nuclear organization within a cell and whether this organization itself can impose cellular function within a tissue remains unknown. To explore the relationship between nuclear organization and tissue architecture and function, we used a model of human mammary epithelial cell acinar morphogenesis. When cultured within a reconstituted basement membrane (rBM), HMT-3522 cells form polarized and growth-arrested tissue-like acini with a central lumen and deposit an endogenous BM. We show that rBM-induced morphogenesis is accompanied by relocalization of the nuclear matrix proteins NuMA, splicing factor SRm160, and cell cycle regulator Rb. These proteins had distinct distribution patterns specific for proliferation, growth arrest, and acini formation, whereas the distribution of the nuclear lamina protein, lamin B, remained unchanged. NuMA relocalized to foci, which coalesced into larger assemblies as morphogenesis progressed. Perturbation of histone acetylation in the acini by trichostatin A treatment altered chromatin structure, disrupted NuMA foci, and induced cell proliferation. Moreover, treatment of transiently permeabilized acini with a NuMA antibody led to the disruption of NuMA foci, alteration of histone acetylation, activation of metalloproteases, and breakdown of the endogenous BM. These results experimentally demonstrate a dynamic interaction between the extracellular matrix, nuclear organization, and tissue phenotype. They further show that rather than passively ref lecting changes in gene expression, nuclear organization itself can modulate the cellular and tissue phenotype.

  18. Item Response Theory with Estimation of the Latent Density Using Davidian Curves

    ERIC Educational Resources Information Center

    Woods, Carol M.; Lin, Nan

    2009-01-01

    Davidian-curve item response theory (DC-IRT) is introduced, evaluated with simulations, and illustrated using data from the Schedule for Nonadaptive and Adaptive Personality Entitlement scale. DC-IRT is a method for fitting unidimensional IRT models with maximum marginal likelihood estimation, in which the latent density is estimated,…

  19. On the Relationship between Classical Test Theory and Item Response Theory: From One to the Other and Back

    ERIC Educational Resources Information Center

    Raykov, Tenko; Marcoulides, George A.

    2016-01-01

    The frequently neglected and often misunderstood relationship between classical test theory and item response theory is discussed for the unidimensional case with binary measures and no guessing. It is pointed out that popular item response models can be directly obtained from classical test theory-based models by accounting for the discrete…

  20. Analysis of Letter Name Knowledge Using Rasch Measurement

    ERIC Educational Resources Information Center

    Bowles, Ryan P.; Skibbe, Lori E.; Justice, Laura M.

    2011-01-01

    Letter name knowledge (LNK) is a key predictor of later reading ability and has been emphasized strongly in recent educational policy. Studies of LNK have implicitly treated it as a unidimensional construct with all letters equally relevant to its measurement. However, some empirical research suggests that contextual factors can affect the…

  1. The Impact of Different Ability Distributions on IRT Preequating.

    ERIC Educational Resources Information Center

    Stocking, Martha L.; Eignor, Daniel R.

    In item response theory (IRT), preequating depends upon item parameter estimate invariance. Three separate simulations, all using the unidimensional three-parameter logistic item response model, were conducted to study the impact of the following variables on preequating: (1) mean differences in ability; (2) multidimensionality in the data; and…

  2. Sequential Dependencies in Categorical Judgments of Radiographic Images

    ERIC Educational Resources Information Center

    Beckstead, Jason W.; Boutis, Kathy; Pecaric, Martin; Pusic, Martin V.

    2017-01-01

    Sequential context effects, the psychological interactions occurring between the events of successive trials when a sequence of similar stimuli are judged, have interested psychologists for decades. It has been well established that individuals exhibit sequential context effects in psychophysical experiments involving unidimensional stimuli.…

  3. Factor structure and dimensionality of the two depression scales in STAR*D using level 1 datasets.

    PubMed

    Bech, P; Fava, M; Trivedi, M H; Wisniewski, S R; Rush, A J

    2011-08-01

    The factor structure and dimensionality of the HAM-D(17) and the IDS-C(30) are as yet uncertain, because psychometric analyses of these scales have been performed without a clear separation between factor structure profile and dimensionality (total scores being a sufficient statistic). The first treatment step (Level 1) in the STAR*D study provided a dataset of 4041 outpatients with DSM-IV nonpsychotic major depression. The HAM-D(17) and IDS-C(30) were evaluated by principal component analysis (PCA) without rotation. Mokken analysis tested the unidimensionality of the IDS-C(6), which corresponds to the unidimensional HAM-D(6.) For both the HAM-D(17) and IDS-C(30), PCA identified a bi-directional factor contrasting the depressive symptoms versus the neurovegetative symptoms. The HAM-D(6) and the corresponding IDS-C(6) symptoms all emerged in the depression factor. Both the HAM-D(6) and IDS-C(6) were found to be unidimensional scales, i.e., their total scores are each a sufficient statistic for the measurement of depressive states. STAR*D used only one medication in Level 1. The unidimensional HAM-D(6) and IDS-C(6) should be used when evaluating the pure clinical effect of antidepressive treatment, whereas the multidimensional HAM-D(17) and IDS-C(30) should be considered when selecting antidepressant treatment. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. A Mokken Scale to Assess Secondary Pupils' Experience of Violence in Terms of Severity

    ERIC Educational Resources Information Center

    Mooij, Ton

    2012-01-01

    Violence assessment can potentially be improved by Item Response Theory, that is, ordinal Mokken Scale Analysis. The research question is as follows: Does Mokken Scale Analysis of secondary pupils' experience of violence result in a homogeneous, reliable, and valid unidimensional scale that fits all the requirements of Mokken scaling? The method…

  5. An Investigation of Computer Anxiety by Gender and Grade.

    ERIC Educational Resources Information Center

    King, John; Bond, Trevor; Blandford, Sonya

    2002-01-01

    Describes a study of Australian students in grades seven, nine, and 11 that used the Computer Anxiety Index (CAIN), to test its unidimensionality and avoid the conceptual confusion of multi-dimensionality. Discusses the use of Rasch analysis, and analyzes differences in grade levels and gender. (Contains 51 references.) (Author/LRW)

  6. Self Concept: An Examination of Structure.

    ERIC Educational Resources Information Center

    Torshen, Kay Pomerance

    This research tested the proposition that self-concept is unidimensional. Joreskog's Unrestricted Maximum Likelihood Factor Analysis applied to 402 fifth-graders' responses to the Sears Self-Concept Inventory, indicated a twelve factor pattern adequately accounted for variance. Restricted Maximum Likelihood Factor Analysis was than applied to…

  7. A Rasch-Based Validation of the Hooper Visual Organization Test in Chinese-Speaking Children

    ERIC Educational Resources Information Center

    Wuang, Yee-Pay; Wang, Li-Chen; Su, Chwen-Yng

    2010-01-01

    The aim of this study was to examine the validation of the Hooper Visual Organization Test (HVOT) for use in children by testing for item fit, unidimensionality, item hierarchy, reliability, and screening capacity. A modified scoring system was devised for the HVOT so that children received some credit for being able to describe the function of…

  8. Multigroup Generalizability Analysis of Verbal, Quantitative, and Nonverbal Ability Tests for Culturally and Linguistically Diverse Students

    ERIC Educational Resources Information Center

    Lakin, Joni M.; Lai, Emily R.

    2012-01-01

    For educators seeking to differentiate instruction, cognitive ability tests sampling multiple content domains, including verbal, quantitative, and nonverbal reasoning, provide superior information about student strengths and weaknesses compared with unidimensional reasoning measures. However, these ability tests have not been fully evaluated with…

  9. Best Design for Multidimensional Computerized Adaptive Testing with the Bifactor Model

    ERIC Educational Resources Information Center

    Seo, Dong Gi; Weiss, David J.

    2015-01-01

    Most computerized adaptive tests (CATs) have been studied using the framework of unidimensional item response theory. However, many psychological variables are multidimensional and might benefit from using a multidimensional approach to CATs. This study investigated the accuracy, fidelity, and efficiency of a fully multidimensional CAT algorithm…

  10. Posterior Predictive Model Checking for Conjunctive Multidimensionality in Item Response Theory

    ERIC Educational Resources Information Center

    Levy, Roy

    2011-01-01

    If data exhibit multidimensionality, key conditional independence assumptions of unidimensional models do not hold. The current work pursues posterior predictive model checking (PPMC) as a tool for criticizing models due to unaccounted for dimensions in data structures that follow conjunctive multidimensional models. These pursuits are couched in…

  11. The Meaning and Measurement of Quality in the Undergraduate Experience.

    ERIC Educational Resources Information Center

    Kuh, George D.

    In an examination of the meaning and measurement of quality in the undergraduate experience, quality is compared with the conceptually similar but distinct concepts of adequacy and excellence. Most of the conceptual frameworks available for assessing quality are essentially unidimensional assessment strategies that rely almost exclusively on…

  12. Estimating Decision Indices Based on Composite Scores

    ERIC Educational Resources Information Center

    Knupp, Tawnya Lee

    2009-01-01

    The purpose of this study was to develop an IRT model that would enable the estimation of decision indices based on composite scores. The composite scores, defined as a combination of unidimensional test scores, were either a total raw score or an average scale score. Additionally, estimation methods for the normal and compound multinomial models…

  13. Performance of the S - [chi][squared] Statistic for Full-Information Bifactor Models

    ERIC Educational Resources Information Center

    Li, Ying; Rupp, Andre A.

    2011-01-01

    This study investigated the Type I error rate and power of the multivariate extension of the S - [chi][squared] statistic using unidimensional and multidimensional item response theory (UIRT and MIRT, respectively) models as well as full-information bifactor (FI-bifactor) models through simulation. Manipulated factors included test length, sample…

  14. Impact of Violation of the Missing-at-Random Assumption on Full-Information Maximum Likelihood Method in Multidimensional Adaptive Testing

    ERIC Educational Resources Information Center

    Han, Kyung T.; Guo, Fanmin

    2014-01-01

    The full-information maximum likelihood (FIML) method makes it possible to estimate and analyze structural equation models (SEM) even when data are partially missing, enabling incomplete data to contribute to model estimation. The cornerstone of FIML is the missing-at-random (MAR) assumption. In (unidimensional) computerized adaptive testing…

  15. Sufficiency and Conditional Estimation of Person Parameters in the Polytomous Rasch Model

    ERIC Educational Resources Information Center

    Andrich, David

    2010-01-01

    Rasch models are characterised by sufficient statistics for all parameters. In the Rasch unidimensional model for two ordered categories, the parameterisation of the person and item is symmetrical and it is readily established that the total scores of a person and item are sufficient statistics for their respective parameters. In contrast, in the…

  16. On the Value of Homogeneous Constructs for Construct Validation, Theory Testing, and the Description of Psychopathology

    ERIC Educational Resources Information Center

    Smith, Gregory T.; McCarthy, Denis M.; Zapolski, Tamika C. B.

    2009-01-01

    The authors argue for a significant shift in how clinical psychology researchers conduct construct validation and theory validation tests. They argue that sound theory and validation tests can best be conducted on measures of unidimensional or homogeneous constructs. Hierarchical organizations of such constructs are useful descriptively and…

  17. Sustainability in the University Student's Mind: Are University Endorsements, Financial Support, and Programs Making a Difference?

    ERIC Educational Resources Information Center

    Perrault, Evan K.; Clark, Scott K.

    2017-01-01

    Despite the increasing awareness that sustainability is an issue needing ongoing attention, and despite millions of dollars spent yearly at universities to promote sustainable behaviors, previous research has found college students have primarily a unidimensional understanding of what sustainability encompasses. The current research sought to…

  18. How to Use Chromatography as a Science Teaching Aid.

    ERIC Educational Resources Information Center

    Ganis, Frank M.

    Presented are five procedures which permit the effective teaching of chromatography with equipment which is readily available, economical, and simple in design. The first procedure involves a study of solute partition in two immiscible solvents and of countercurrent distribution. The second illustrates the use of unidimensional ascending paper…

  19. Dimensions, Patterns, and Personality Correlates of Drug Abuse in an Offender Population.

    ERIC Educational Resources Information Center

    Holland, Terrill R.

    1978-01-01

    Drug abuse scores from prisoners resulted in two factors describing lifetime use of cannabis versus opiates. Analysis of Minnesota Multiphasic Personality Inventory (MMPI) profiles versus drug abuse patterns indicated moderate, unidimensional relationship between variables. MMPI profiles of opiate users were similar to those identified in research…

  20. Implementation and Measurement Efficiency of Multidimensional Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Wang, Wen-Chung; Chen, Po-Hsi

    2004-01-01

    Multidimensional adaptive testing (MAT) procedures are proposed for the measurement of several latent traits by a single examination. Bayesian latent trait estimation and adaptive item selection are derived. Simulations were conducted to compare the measurement efficiency of MAT with those of unidimensional adaptive testing and random…

  1. A Prospective Study Investigating the Impact of School Belonging Factors on Negative Affect in Adolescents

    ERIC Educational Resources Information Center

    Shochet, Ian M.; Smith, Coral L.; Furlong, Michael J.; Homel, Ross

    2011-01-01

    School belonging, measured as a unidimensional construct, is an important predictor of negative affective problems in adolescents, including depression and anxiety symptoms. A recent study found that one such measure, the Psychological Sense of School Membership scale, actually comprises three factors: Caring Relations, Acceptance, and Rejection.…

  2. Shaping the longitudinal intensity pattern of Cartesian beams in lossless and lossy media

    NASA Astrophysics Data System (ADS)

    Corato-Zanarella, Mateus; Corato-Zanarella, Henrique; Zamboni-Rached, Michel

    2017-09-01

    Several applications, such as optical tweezers and atom guiding, benefit from techniques that allow the engineering of spatial field profiles, in particular their longitudinal intensity patterns. In cylindrical coordinates, methods such as frozen waves allow an advanced control of beam characteristics, but in Cartesian coordinates there is no analogous technique. Since Cartesian beams may also be useful in applications, we develop here a method to modulate on demand the longitudinal intensity pattern of any (initially) unidimensional Cartesian beam with concentrated angular spectrum (thus encompassing all unidimensional paraxial beams) in lossless and lossy media. To this end, we write the total beam as a product of two unidimensional beams and explore the degree of freedom provided by the additional Cartesian coordinate. While in the plane where this coordinate is zero the chosen unidimensional beam keeps its structure with the additional desired intensity modulation, a sinusoidal-like oscillation appears in the direction of this variable and creates a spot whose size is tunable. Examples with Gaussian and Airy beams are presented and their corresponding experimental demonstrations in free-space are performed to show the validity of the method.

  3. An Investigation of Computer Anxiety by Gender and Grade.

    ERIC Educational Resources Information Center

    King, John; Bond, Trevor; Blandford, Sonya

    2002-01-01

    Describes a study of Australian students in grades seven, nine, and 11 that used the Computer Anxiety Index (CAIN), to test its unidimensionality and avoid the conceptual confusion of multi-dimensionality. Discusses the use of Rasch analysis, and analyzes differences in grade levels and gender. (Contains 51 references.) (Author/LRW)

  4. Using Necessary Information to Identify Item Dependence in Passage-Based Reading Comprehension Tests

    ERIC Educational Resources Information Center

    Baldonado, Angela Argo; Svetina, Dubravka; Gorin, Joanna

    2015-01-01

    Applications of traditional unidimensional item response theory models to passage-based reading comprehension assessment data have been criticized based on potential violations of local independence. However, simple rules for determining dependency, such as including all items associated with a particular passage, may overestimate the dependency…

  5. When Cognitive Diagnosis Meets Computerized Adaptive Testing: CD-CAT

    ERIC Educational Resources Information Center

    Cheng, Ying

    2009-01-01

    Computerized adaptive testing (CAT) is a mode of testing which enables more efficient and accurate recovery of one or more latent traits. Traditionally, CAT is built upon Item Response Theory (IRT) models that assume unidimensionality. However, the problem of how to build CAT upon latent class models (LCM) has not been investigated until recently,…

  6. A Study of Confidence and Accuracy Using the Rasch Modeling Procedures. Research Report. ETS RR-08-42

    ERIC Educational Resources Information Center

    Paek, Insu; Lee, Jihyun; Stankov, Lazar; Wilson, Mark

    2008-01-01

    This study investigated the relationship between students' actual performance (accuracy) and their subjective judgments of accuracy (confidence) on selected English language proficiency tests. The unidimensional and multidimensional IRT Rasch approaches were used to model the discrepancy between confidence and accuracy at the item and test level…

  7. Robustness of Hierarchical Modeling of Skill Association in Cognitive Diagnosis Models

    ERIC Educational Resources Information Center

    Templin, Jonathan L.; Henson, Robert A.; Templin, Sara E.; Roussos, Louis

    2008-01-01

    Several types of parameterizations of attribute correlations in cognitive diagnosis models use the reduced reparameterized unified model. The general approach presumes an unconstrained correlation matrix with K(K - 1)/2 parameters, whereas the higher order approach postulates K parameters, imposing a unidimensional structure on the correlation…

  8. Application of the Bifactor Model to Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Seo, Dong Gi

    2011-01-01

    Most computerized adaptive tests (CAT) have been studied under the framework of unidimensional item response theory. However, many psychological variables are multidimensional and might benefit from using a multidimensional approach to CAT. In addition, a number of psychological variables (e.g., quality of life, depression) can be conceptualized…

  9. Lord-Wingersky Algorithm Version 2.0 for Hierarchical Item Factor Models with Applications in Test Scoring, Scale Alignment, and Model Fit Testing. CRESST Report 830

    ERIC Educational Resources Information Center

    Cai, Li

    2013-01-01

    Lord and Wingersky's (1984) recursive algorithm for creating summed score based likelihoods and posteriors has a proven track record in unidimensional item response theory (IRT) applications. Extending the recursive algorithm to handle multidimensionality is relatively simple, especially with fixed quadrature because the recursions can be defined…

  10. Limits on Log Cross-Product Ratios for Item Response Models. Research Report. ETS RR-06-10

    ERIC Educational Resources Information Center

    Haberman, Shelby J.; Holland, Paul W.; Sinharay, Sandip

    2006-01-01

    Bounds are established for log cross-product ratios (log odds ratios) involving pairs of items for item response models. First, expressions for bounds on log cross-product ratios are provided for unidimensional item response models in general. Then, explicit bounds are obtained for the Rasch model and the two-parameter logistic (2PL) model.…

  11. Development and Validation of a 2 x 2 Model of Time-Related Academic Behavior: Procrastination and Timely Engagement

    ERIC Educational Resources Information Center

    Strunk, Kamden K.; Cho, YoonJung; Steele, Misty R.; Bridges, Stacey L.

    2013-01-01

    Procrastination is an educational concern for classroom instructors because of its negative psychological and academic impacts on students. However, the traditional view of procrastination as a unidimensional construct is insufficient in two regards. First, the construct needs to be viewed more broadly as time-related academic behavior,…

  12. Using the Rasch Measurement Model To Investigate the Construct of Motor Ability in Young Children.

    ERIC Educational Resources Information Center

    Hands, Beth; Larkin, Dawne

    2001-01-01

    Used the Rasch measurement model to explore the construct of a general motor ability in 332 5- and 6-year-old Australian children performing 24 motor skills. After categorizing data, two different, unidimensional scales were created, one for boys and one for girls. (SLD)

  13. A Rasch Analysis of the Academic Self-Concept Questionnaire

    ERIC Educational Resources Information Center

    Joyce, Tan Bei Yu; Yates, Shirley M.

    2007-01-01

    This study used the Rasch model to assess the unidimensionality and item-person fit of an Academic Self-Concept Questionnaire (ASCQ) that is based on the Confucian Heritage Culture (CHC) perspective. Knowledge of the relationship between academic achievement and academic self-concept is particularly useful because academic achievement is…

  14. The Twofold Multidimensionality of Academic Self-Concept: Domain Specificity and Separation between Competence and Affect Components

    ERIC Educational Resources Information Center

    Arens, A. Katrin; Yeung, Alexander Seeshing; Craven, Rhonda G.; Hasselhorn, Marcus

    2011-01-01

    Academic self-concept is consistently proven to be multidimensional rather than unidimensional as it is domain specific in nature. However, each specific self-concept domain may be further separated into competence and affect components. This study examines the twofold multidimensionality of academic self-concept (i.e., its domain specificity and…

  15. Acculturation Style and Alcohol Use among African American College Students: An Exploration of Potential Moderators

    ERIC Educational Resources Information Center

    Abdullah, Tahirah; Brown, Tamara L.

    2012-01-01

    This study examined whether a relationship exists between acculturation and alcohol use among African American college students and if the relationship varies by religiosity and gender. Most researchers use unidimensional African American acculturation measures that cannot capture the construct's complexity; this study is the first to use a…

  16. Confirming the Multidimensionality of Psychologically Controlling Parenting among Chinese-American Mothers: Love Withdrawal, Guilt Induction, and Shaming

    ERIC Educational Resources Information Center

    Yu, Jing; Cheah, Charissa S. L.; Hart, Craig H.; Sun, Shuyan; Olsen, Joseph A.

    2015-01-01

    Despite the theoretical conceptualization of parental psychological control as a multidimensional construct, the majority of previous studies have examined psychological control as a unidimensional scale. Moreover, the conceptualization of shaming and its associations with love withdrawal and guilt induction are unclear. The current study aimed to…

  17. A Simulation Study on the Performance of Four Multidimensional IRT Scale Linking Methods

    ERIC Educational Resources Information Center

    Wei, Youhua

    2008-01-01

    Scale linking is the process of developing the connection between scales of two or more sets of parameter estimates obtained from separate test calibrations. It is the prerequisite for many applications of IRT, such as test equating and differential item functioning analysis. Unidimensional scale linking methods have been studied and applied…

  18. Measuring Learned Resourcefulness in College Students: Factor Structure of the Self-Control Schedule (SCS)

    ERIC Educational Resources Information Center

    McWhirter, Benedict T.; Burrow-Sanchez, Jason J.; Townsend, Katesy C.

    2008-01-01

    Rosenbaum's Self-Control Schedule (SCS) has been used as a unidimensional measure of Learned Resourcefulness (LR) in previous research. In this study we clarified the factor structure of the SCS among college students (N = 583) by conducting a principal axis factor analysis with oblique (Oblimin) rotation on the SCS. Results revealed a…

  19. Comparing Three Estimation Methods for the Three-Parameter Logistic IRT Model

    ERIC Educational Resources Information Center

    Lamsal, Sunil

    2015-01-01

    Different estimation procedures have been developed for the unidimensional three-parameter item response theory (IRT) model. These techniques include the marginal maximum likelihood estimation, the fully Bayesian estimation using Markov chain Monte Carlo simulation techniques, and the Metropolis-Hastings Robbin-Monro estimation. With each…

  20. Multidimensional Item Response Theory Models in Vocational Interest Measurement: An Illustration Using the AIST-R

    ERIC Educational Resources Information Center

    Wetzel, Eunike; Hell, Benedikt

    2014-01-01

    Vocational interest inventories are commonly analyzed using a unidimensional approach, that is, each subscale is analyzed separately. However, the theories on which these inventories are based often postulate specific relationships between the interest traits. This article presents a multidimensional approach to the analysis of vocational interest…

  1. Mokken Scale Analysis Using Hierarchical Clustering Procedures

    ERIC Educational Resources Information Center

    van Abswoude, Alexandra A. H.; Vermunt, Jeroen K.; Hemker, Bas T.; van der Ark, L. Andries

    2004-01-01

    Mokken scale analysis (MSA) can be used to assess and build unidimensional scales from an item pool that is sensitive to multiple dimensions. These scales satisfy a set of scaling conditions, one of which follows from the model of monotone homogeneity. An important drawback of the MSA program is that the sequential item selection and scale…

  2. Acculturation Style and Alcohol Use among African American College Students: An Exploration of Potential Moderators

    ERIC Educational Resources Information Center

    Abdullah, Tahirah; Brown, Tamara L.

    2012-01-01

    This study examined whether a relationship exists between acculturation and alcohol use among African American college students and if the relationship varies by religiosity and gender. Most researchers use unidimensional African American acculturation measures that cannot capture the construct's complexity; this study is the first to use a…

  3. Chemistry Education: Ten Facets to Shape Us

    ERIC Educational Resources Information Center

    Talanquer, Vicente

    2013-01-01

    The chemistry knowledge that we want our students to develop is rich, complex, and multifaceted. However, some teachers and instructors at the secondary school and college levels approach it in rather rigid and unidimensional ways. The central goal of this contribution is to describe and discuss 10 different complementary perspectives or…

  4. Effortful Control in "Hot" and "Cool" Tasks Differentially Predicts Children's Behavior Problems and Academic Performance

    ERIC Educational Resources Information Center

    Kim, Sanghag; Nordling, Jamie Koenig; Yoon, Jeung Eun; Boldt, Lea J.; Kochanska, Grazyna

    2013-01-01

    Effortful control (EC), the capacity to deliberately suppress a dominant response and perform a subdominant response, rapidly developing in toddler and preschool age, has been shown to be a robust predictor of children's adjustment. Not settled, however, is whether a view of EC as a heterogeneous rather than unidimensional construct may offer…

  5. Posterior Predictive Model Checking for Multidimensionality in Item Response Theory

    ERIC Educational Resources Information Center

    Levy, Roy; Mislevy, Robert J.; Sinharay, Sandip

    2009-01-01

    If data exhibit multidimensionality, key conditional independence assumptions of unidimensional models do not hold. The current work pursues posterior predictive model checking, a flexible family of model-checking procedures, as a tool for criticizing models due to unaccounted for dimensions in the context of item response theory. Factors…

  6. Posterior Predictive Model Checking for Conjunctive Multidimensionality in Item Response Theory

    ERIC Educational Resources Information Center

    Levy, Roy

    2011-01-01

    If data exhibit multidimensionality, key conditional independence assumptions of unidimensional models do not hold. The current work pursues posterior predictive model checking (PPMC) as a tool for criticizing models due to unaccounted for dimensions in data structures that follow conjunctive multidimensional models. These pursuits are couched in…

  7. Absolute Identification by Relative Judgment

    ERIC Educational Resources Information Center

    Stewart, Neil; Brown, Gordon D. A.; Chater, Nick

    2005-01-01

    In unidimensional absolute identification tasks, participants identify stimuli that vary along a single dimension. Performance is surprisingly poor compared with discrimination of the same stimuli. Existing models assume that identification is achieved using long-term representations of absolute magnitudes. The authors propose an alternative…

  8. Item Response Theory with Estimation of the Latent Density Using Davidian Curves

    ERIC Educational Resources Information Center

    Woods, Carol M.; Lin, Nan

    2009-01-01

    Davidian-curve item response theory (DC-IRT) is introduced, evaluated with simulations, and illustrated using data from the Schedule for Nonadaptive and Adaptive Personality Entitlement scale. DC-IRT is a method for fitting unidimensional IRT models with maximum marginal likelihood estimation, in which the latent density is estimated,…

  9. Satisfaction Ratings of QOLPAV: Psychometric Properties Based on the Graded Response Model

    ERIC Educational Resources Information Center

    Chen, Ssu-Kuang; Hwang, Fang-Ming; Lin, Sunny S. J.

    2013-01-01

    A scale measuring quality of life (QOL) is important in adolescent research. Using the graded response model (GRM), this study evaluates the psychometric properties of the satisfaction ratings of the Quality of Life Profile Adolescent Version (QOLPAV). Data for 1,392 adolescents were used to check IRT assumptions such as unidimensionality and…

  10. Effortful Control in "Hot" and "Cool" Tasks Differentially Predicts Children's Behavior Problems and Academic Performance

    ERIC Educational Resources Information Center

    Kim, Sanghag; Nordling, Jamie Koenig; Yoon, Jeung Eun; Boldt, Lea J.; Kochanska, Grazyna

    2013-01-01

    Effortful control (EC), the capacity to deliberately suppress a dominant response and perform a subdominant response, rapidly developing in toddler and preschool age, has been shown to be a robust predictor of children's adjustment. Not settled, however, is whether a view of EC as a heterogeneous rather than unidimensional construct may offer…

  11. Using Logistic Approximations of Marginal Trace Lines to Develop Short Assessments

    ERIC Educational Resources Information Center

    Stucky, Brian D.; Thissen, David; Edelen, Maria Orlando

    2013-01-01

    Test developers often need to create unidimensional scales from multidimensional data. For item analysis, "marginal trace lines" capture the relation with the general dimension while accounting for nuisance dimensions and may prove to be a useful technique for creating short-form tests. This article describes the computations needed to obtain…

  12. Community Agricultural Processing Services: A Reflection of Urban Differentiation or County Agricultural Structure.

    ERIC Educational Resources Information Center

    Moxley, Robert L.; Calloway, Michael O.

    Questionnaire data from 81 North Carolina communities were analyzed in 1981 to test the hypothesis that 5 institutional subcategories (education, general community services, transportation, agricultural services, and health and sanitation) exhibit the underlying characteristic of unidimensionality and that they reflect comparable levels of…

  13. The Twofold Multidimensionality of Academic Self-Concept: Domain Specificity and Separation between Competence and Affect Components

    ERIC Educational Resources Information Center

    Arens, A. Katrin; Yeung, Alexander Seeshing; Craven, Rhonda G.; Hasselhorn, Marcus

    2011-01-01

    Academic self-concept is consistently proven to be multidimensional rather than unidimensional as it is domain specific in nature. However, each specific self-concept domain may be further separated into competence and affect components. This study examines the twofold multidimensionality of academic self-concept (i.e., its domain specificity and…

  14. Multidimensional CAT Item Selection Methods for Domain Scores and Composite Scores: Theory and Applications

    ERIC Educational Resources Information Center

    Yao, Lihua

    2012-01-01

    Multidimensional computer adaptive testing (MCAT) can provide higher precision and reliability or reduce test length when compared with unidimensional CAT or with the paper-and-pencil test. This study compared five item selection procedures in the MCAT framework for both domain scores and overall scores through simulation by varying the structure…

  15. Graded Response Model Based on the Logistic Positive Exponent Family of Models for Dichotomous Responses

    ERIC Educational Resources Information Center

    Samejima, Fumiko

    2008-01-01

    Samejima ("Psychometrika "65:319--335, 2000) proposed the logistic positive exponent family of models (LPEF) for dichotomous responses in the unidimensional latent space. The objective of the present paper is to propose and discuss a graded response model that is expanded from the LPEF, in the context of item response theory (IRT). This…

  16. Confirming the Multidimensionality of Psychologically Controlling Parenting among Chinese-American Mothers: Love Withdrawal, Guilt Induction, and Shaming

    ERIC Educational Resources Information Center

    Yu, Jing; Cheah, Charissa S. L.; Hart, Craig H.; Sun, Shuyan; Olsen, Joseph A.

    2015-01-01

    Despite the theoretical conceptualization of parental psychological control as a multidimensional construct, the majority of previous studies have examined psychological control as a unidimensional scale. Moreover, the conceptualization of shaming and its associations with love withdrawal and guilt induction are unclear. The current study aimed to…

  17. Knowledge Contribution in Virtual Communities: Accounting for Multiple Dimensions of Social Presence through Social Identity

    ERIC Educational Resources Information Center

    Shen, Kathy Ning; Yu, Angela Yan; Khalifa, Mohamed

    2010-01-01

    Integrating social presence theory and social identity theory, this study brings system design and social influence aspects together to explain their joint effects on knowledge contribution in virtual communities (VCs). Different from most prior information systems (IS) research that adopts a uni-dimensional approach and restricts social presence…

  18. A Rasch-Based Validation of the Hooper Visual Organization Test in Chinese-Speaking Children

    ERIC Educational Resources Information Center

    Wuang, Yee-Pay; Wang, Li-Chen; Su, Chwen-Yng

    2010-01-01

    The aim of this study was to examine the validation of the Hooper Visual Organization Test (HVOT) for use in children by testing for item fit, unidimensionality, item hierarchy, reliability, and screening capacity. A modified scoring system was devised for the HVOT so that children received some credit for being able to describe the function of…

  19. Ramsay Curve IRT for Likert-Type Data

    ERIC Educational Resources Information Center

    Woods, Carol M.

    2007-01-01

    Ramsay curve item response theory (RC-IRT) was recently developed to detect and correct for nonnormal latent variables when unidimensional IRT models are fitted to data using maximum marginal likelihood estimation. The purpose of this research is to evaluate the performance of RC-IRT for Likert-type item responses with varying test lengths, sample…

  20. Understanding Patterns of Evolution Acceptance--A New Implementation of the Measure of Acceptance of the Theory of Evolution (MATE) with Midwestern University Students

    ERIC Educational Resources Information Center

    Romine, William L.; Walter, Emily M.; Bosse, Ephiram; Todd, Amber N.

    2017-01-01

    We validate the Measure of Acceptance of the Theory of Evolution (MATE) on undergraduate students using the Rasch model and utilize the MATE to explore qualitatively how students express their acceptance of evolution. At least 24 studies have used the MATE, most with the assumption that it is unidimensional. However, we found that the MATE is best…

  1. Using Perceived Health to Test the Construct-Related Validity of Global Quality of Life

    ERIC Educational Resources Information Center

    Beckie, Theresa M.; Hayduk, Leslie A.

    2004-01-01

    Quality of life (QOL) is considered as a global, yet unidimensional, subjective assessment of one's satisfaction with life. We examine the construct validity of the available indicators of global QOL by constructing a causal model in which QOL is viewed as causally responding to several dimensions of perceived health. Global QOL is measured with…

  2. Multidimensional latent trait linear mixed model: an application in clinical studies with multivariate longitudinal outcomes.

    PubMed

    Wang, Jue; Luo, Sheng

    2017-09-10

    Multilevel item response theory (MLIRT) models have been widely used to analyze the multivariate longitudinal data of mixed types (e.g., categorical and continuous) in clinical studies. The MLIRT models often have unidimensional assumption, that is, the multiple outcomes are clinical manifestations of a univariate latent variable. However, the unidimensional assumption may be unrealistic because some diseases may be heterogeneous and characterized by multiple impaired domains with variable clinical symptoms and disease progressions. We relax this assumption and propose a multidimensional latent trait linear mixed model (MLTLMM) to allow multiple latent variables and within-item multidimensionality (one outcome can be a manifestation of more than one latent variable). We conduct extensive simulation studies to assess the unidimensional MLIRT model and the proposed MLTLMM model. The simulation studies suggest that the MLTLMM model outperforms unidimensional model when the multivariate longitudinal outcomes are manifested by multiple latent variables. The proposed model is applied to two motivating studies of amyotrophic lateral sclerosis: a clinical trial of ceftriaxone and the Pooled Resource Open-Access ALS Clinical Trials database. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  3. Multidimensional Models for Matrix-Sampled Reading Tasks.

    ERIC Educational Resources Information Center

    Palaszewski, Bo

    The International Adult Literacy Survey (IALS) was conducted in 1994 in seven European countries with the aim of producing literacy profiles to be used in individual national analyses as well as in international comparisons. It was assumed that the test items could be divided into three unidimensional scales corresponding to the aspects…

  4. Development and Validation of a 2 x 2 Model of Time-Related Academic Behavior: Procrastination and Timely Engagement

    ERIC Educational Resources Information Center

    Strunk, Kamden K.; Cho, YoonJung; Steele, Misty R.; Bridges, Stacey L.

    2013-01-01

    Procrastination is an educational concern for classroom instructors because of its negative psychological and academic impacts on students. However, the traditional view of procrastination as a unidimensional construct is insufficient in two regards. First, the construct needs to be viewed more broadly as time-related academic behavior,…

  5. IRTPRO 2.1 for Windows (Item Response Theory for Patient-Reported Outcomes)

    ERIC Educational Resources Information Center

    Paek, Insu; Han, Kyung T.

    2013-01-01

    This article reviews a new item response theory (IRT) model estimation program, IRTPRO 2.1, for Windows that is capable of unidimensional and multidimensional IRT model estimation for existing and user-specified constrained IRT models for dichotomously and polytomously scored item response data. (Contains 1 figure and 2 notes.)

  6. The Multivariate Nature of Professional Job Satisfaction.

    ERIC Educational Resources Information Center

    Wood, Donald A.; LeBold, William K.

    Discussed are two theories of professional job satisfaction--(1) unidimensional and (2) multidimensional with special reference to Herzberg's two factor theory. A national sample of over 3,000 engineering graduates responded to a questionnaire and satisfaction index. Analysis of results revealed that job satisfaction is multidimensional. Job…

  7. Impact of Diagnosticity on the Adequacy of Models for Cognitive Diagnosis under a Linear Attribute Structure: A Simulation Study

    ERIC Educational Resources Information Center

    de La Torre, Jimmy; Karelitz, Tzur M.

    2009-01-01

    Compared to unidimensional item response models (IRMs), cognitive diagnostic models (CDMs) based on latent classes represent examinees' knowledge and item requirements using discrete structures. This study systematically examines the viability of retrofitting CDMs to IRM-based data with a linear attribute structure. The study utilizes a procedure…

  8. Development and Initial Validation of the Inventory of Microaggressions against Black Individuals

    ERIC Educational Resources Information Center

    Mercer, Sterett H.; Zeigler-Hill, Virgil; Wallace, Marion; Hayes, DeMarquis M.

    2011-01-01

    The present article describes the development and initial validation of the Inventory of Microaggressions Against Black Individuals (IMABI) using a sample of 385 undergraduates who self-identified as Black or African American. The IMABI is a 14-item, unidimensional measure of racial microaggressions that captures both microinsults and…

  9. Identifying Country-Specific Cultures of Physics Education: A Differential Item Functioning Approach

    ERIC Educational Resources Information Center

    Mesic, Vanes

    2012-01-01

    In international large-scale assessments of educational outcomes, student achievement is often represented by unidimensional constructs. This approach allows for drawing general conclusions about country rankings with respect to the given achievement measure, but it typically does not provide specific diagnostic information which is necessary for…

  10. Effect Size Measures for Differential Item Functioning in a Multidimensional IRT Model

    ERIC Educational Resources Information Center

    Suh, Youngsuk

    2016-01-01

    This study adapted an effect size measure used for studying differential item functioning (DIF) in unidimensional tests and extended the measure to multidimensional tests. Two effect size measures were considered in a multidimensional item response theory model: signed weighted P-difference and unsigned weighted P-difference. The performance of…

  11. Community Agricultural Processing Services: A Reflection of Urban Differentiation or County Agricultural Structure.

    ERIC Educational Resources Information Center

    Moxley, Robert L.; Calloway, Michael O.

    Questionnaire data from 81 North Carolina communities were analyzed in 1981 to test the hypothesis that 5 institutional subcategories (education, general community services, transportation, agricultural services, and health and sanitation) exhibit the underlying characteristic of unidimensionality and that they reflect comparable levels of…

  12. On the Relationship between Classical Test Theory and Item Response Theory: From One to the Other and Back

    ERIC Educational Resources Information Center

    Raykov, Tenko; Marcoulides, George A.

    2016-01-01

    The frequently neglected and often misunderstood relationship between classical test theory and item response theory is discussed for the unidimensional case with binary measures and no guessing. It is pointed out that popular item response models can be directly obtained from classical test theory-based models by accounting for the discrete…

  13. Variability in Parameter Estimates and Model Fit across Repeated Allocations of Items to Parcels

    ERIC Educational Resources Information Center

    Sterba, Sonya K.; MacCallum, Robert C.

    2010-01-01

    Different random or purposive allocations of items to parcels within a single sample are thought not to alter structural parameter estimates as long as items are unidimensional and congeneric. If, additionally, numbers of items per parcel and parcels per factor are held fixed across allocations, different allocations of items to parcels within a…

  14. Educational Mismatch of Graduates: A Multidimensional and Fuzzy Indicator

    ERIC Educational Resources Information Center

    Betti, Gianni; D'Agostino, Antonella; Neri, Laura

    2011-01-01

    In this paper we attempt to measure the educational mismatch, seen as a problem of overeducation, using a multidimensional and fuzzy methodology. Educational mismatch can be difficult to measure because many factors can converge to its definition and the traditional unidimensional indicators presented in literature can offer a restricted view of…

  15. The Conceptualization and Measurement of Interpersonal Communication Satisfaction.

    ERIC Educational Resources Information Center

    Hecht, Michael L.

    1978-01-01

    Reports on the development and testing of a measure of interpersonal communication satisfaction. The 19-item, unidimensional inventory is shown to exhibit a high degree of reliability and validity when used to measure communication satisfaction with actual and recalled conversations with another perceived to be a friend, acquaintance, or stranger.…

  16. Child's Positive and Negative Impacts on Parents--A Person-Oriented Approach to Understanding Temperament in Preschool Children with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Bostrom, P. K.; Broberg, M.; Bodin, L.

    2011-01-01

    Background: Despite previous efforts to understand temperament in children with intellectual disability (ID), and how child temperament may affect parents, the approach has so far been unidimensional. Child temperament has been considered in relation to diagnosis, with the inherent risk of overlooking individual variation of children's temperament…

  17. Psychometric Properties of Measures of Team Diversity with Likert Data

    ERIC Educational Resources Information Center

    Deng, Lifang; Marcoulides, George A.; Yuan, Ke-Hai

    2015-01-01

    Certain diversity among team members is beneficial to the growth of an organization. Multiple measures have been proposed to quantify diversity, although little is known about their psychometric properties. This article proposes several methods to evaluate the unidimensionality and reliability of three measures of diversity. To approximate the…

  18. Application of a General Polytomous Testlet Model to the Reading Section of a Large-Scale English Language Assessment. Research Report. ETS RR-10-21

    ERIC Educational Resources Information Center

    Li, Yanmei; Li, Shuhong; Wang, Lin

    2010-01-01

    Many standardized educational tests include groups of items based on a common stimulus, known as "testlets". Standard unidimensional item response theory (IRT) models are commonly used to model examinees' responses to testlet items. However, it is known that local dependence among testlet items can lead to biased item parameter estimates…

  19. An Investigation of Sample Size Splitting on ATFIND and DIMTEST

    ERIC Educational Resources Information Center

    Socha, Alan; DeMars, Christine E.

    2013-01-01

    Modeling multidimensional test data with a unidimensional model can result in serious statistical errors, such as bias in item parameter estimates. Many methods exist for assessing the dimensionality of a test. The current study focused on DIMTEST. Using simulated data, the effects of sample size splitting for use with the ATFIND procedure for…

  20. Robustness of Hierarchical Modeling of Skill Association in Cognitive Diagnosis Models

    ERIC Educational Resources Information Center

    Templin, Jonathan L.; Henson, Robert A.; Templin, Sara E.; Roussos, Louis

    2008-01-01

    Several types of parameterizations of attribute correlations in cognitive diagnosis models use the reduced reparameterized unified model. The general approach presumes an unconstrained correlation matrix with K(K - 1)/2 parameters, whereas the higher order approach postulates K parameters, imposing a unidimensional structure on the correlation…

  1. Dimensionality of Thoughts of Death and Suicide: Evidence from a Study of Homeless Adolescents

    ERIC Educational Resources Information Center

    Yoder, Kevin A.; Whitbeck, Les B.; Hoyt, Dan R.

    2008-01-01

    This study used data from a sample of 444 homeless adolescents to determine whether thoughts of death and suicide form one construct (unidimensionality) or two distinct but correlated constructs (multi-dimensionality). Thoughts of death and suicide were common in the sample; over two-thirds of the adolescents positively endorsed at least one of…

  2. A Prospective Study Investigating the Impact of School Belonging Factors on Negative Affect in Adolescents

    ERIC Educational Resources Information Center

    Shochet, Ian M.; Smith, Coral L.; Furlong, Michael J.; Homel, Ross

    2011-01-01

    School belonging, measured as a unidimensional construct, is an important predictor of negative affective problems in adolescents, including depression and anxiety symptoms. A recent study found that one such measure, the Psychological Sense of School Membership scale, actually comprises three factors: Caring Relations, Acceptance, and Rejection.…

  3. Individualism and the Emerging "Modern" Ideology of Death.

    ERIC Educational Resources Information Center

    Kearl, Michael C.; Harris, Richard

    1981-01-01

    Begins with a theoretical elaboration of individualism. Argues its development is associated with an emergent death ideology emphasizing personal control. In two national samples attitudes toward suicide, abortion and the right to die scaled unidimensionally. Results indicated indices of individualism were the best predictors of position on this…

  4. A Mokken Scale to Assess Secondary Pupils' Experience of Violence in Terms of Severity

    ERIC Educational Resources Information Center

    Mooij, Ton

    2012-01-01

    Violence assessment can potentially be improved by Item Response Theory, that is, ordinal Mokken Scale Analysis. The research question is as follows: Does Mokken Scale Analysis of secondary pupils' experience of violence result in a homogeneous, reliable, and valid unidimensional scale that fits all the requirements of Mokken scaling? The method…

  5. Personality Correlates of Aggression: Evidence from Measures of the Five-Factor Model, UPPS Model of Impulsivity, and BIS/BAS

    ERIC Educational Resources Information Center

    Miller, Joshua D.; Zeichner, Amos; Wilson, Lauren F.

    2012-01-01

    Although many studies of personality and aggression focus on multidimensional traits and higher order personality disorders (e.g., psychopathy), lower order, unidimensional traits may provide more precision in identifying specific aspects of personality that relate to aggression. The current study includes a comprehensive measurement of lower…

  6. Multiple-Group Noncompensatory Differential Item Functioning in Raju's Differential Functioning of Items and Tests

    ERIC Educational Resources Information Center

    Oshima, T. C.; Wright, Keith; White, Nick

    2015-01-01

    Raju, van der Linden, and Fleer (1995) introduced a framework for differential functioning of items and tests (DFIT) for unidimensional dichotomous models. Since then, DFIT has been shown to be a quite versatile framework as it can handle polytomous as well as multidimensional models both at the item and test levels. However, DFIT is still limited…

  7. Some Better Practices for Measuring Racial and Ethnic Identity Constructs

    ERIC Educational Resources Information Center

    Helms, Janet E.

    2007-01-01

    Racial and ethnic identity (REI) measures are in danger of becoming conceptually meaningless because of evaluators' insistence that they conform to measurement models intended to assess unidimensional constructs, rather than the multidimensional constructs necessary to capture the complexity of internalized racial or cultural socialization. Some…

  8. Assessing Dimensionality of a Set of Items--Comparison of Different Approaches.

    ERIC Educational Resources Information Center

    Nandakumar, Ratna

    The performance of the following four methodologies for assessing unidimensionality was examined: (1) DIMTEST; (2) the approach of P. W. Holland and P. R. Rosenbaum; (3) linear factor analysis; and (4) non-linear factor analysis. Each method is examined and compared with other methods using simulated data sets and real data sets. Seven data sets,…

  9. Measuring Learned Resourcefulness in College Students: Factor Structure of the Self-Control Schedule (SCS)

    ERIC Educational Resources Information Center

    McWhirter, Benedict T.; Burrow-Sanchez, Jason J.; Townsend, Katesy C.

    2008-01-01

    Rosenbaum's Self-Control Schedule (SCS) has been used as a unidimensional measure of Learned Resourcefulness (LR) in previous research. In this study we clarified the factor structure of the SCS among college students (N = 583) by conducting a principal axis factor analysis with oblique (Oblimin) rotation on the SCS. Results revealed a…

  10. Assessing Dimensionality of a Set of Items--Comparison of Different Approaches.

    ERIC Educational Resources Information Center

    Nandakumar, Ratna

    Performance in assessing the unidimensionality of tests was examined for four methods: (1) W. F. Stout's procedure (1987); (2) the approach of P. W. Holland and P. R. Rosenbaum (1986); (3) linear factor analysis; and (4) non-linear factor analysis. Each method was examined and compared with the others using simulated and real test data. Seven data…

  11. Examining Measurement Properties of an English Self-Efficacy Scale for English Language Learners in Korea

    ERIC Educational Resources Information Center

    Wang, Chuang; Kim, Do-Hong; Bong, Mimi; Ahn, Hyun Seon

    2013-01-01

    This study provides evidence for the validity of the Questionnaire of English Self-Efficacy in a sample of 167 college students in Korea. Results show that the scale measures largely satisfy the Rasch model for unidimensionality. The rating scale appeared to function effectively. The item hierarchy was consistent with the expected item order. The…

  12. Semi-Nonparametric Methods for Detecting Latent Non-Normality: A Fusion of Latent Trait and Ordered Latent Class Modeling

    ERIC Educational Resources Information Center

    Schmitt, J. Eric; Mehta, Paras D.; Aggen, Steven H.; Kubarych, Thomas S.; Neale, Michael C.

    2006-01-01

    Ordered latent class analysis (OLCA) can be used to approximate unidimensional latent distributions. The main objective of this study is to evaluate the method of OLCA in detecting non-normality of an unobserved continuous variable (i.e., a common factor) used to explain the covariation between dichotomous item-level responses. Using simulation,…

  13. Development and Application of Methods for Estimating Operating Characteristics of Discrete Test Item Responses without Assuming any Mathematical Form.

    ERIC Educational Resources Information Center

    Samejima, Fumiko

    In latent trait theory the latent space, or space of the hypothetical construct, is usually represented by some unidimensional or multi-dimensional continuum of real numbers. Like the latent space, the item response can either be treated as a discrete variable or as a continuous variable. Latent trait theory relates the item response to the latent…

  14. A General Model for Free Response Data

    ERIC Educational Resources Information Center

    Samejima, Fumiko

    1972-01-01

    This paper proposes a general model for free-response data collected for measuring a specified unidimensional psychological process; systematizes situations which vary with respect to the scoring level of items; and finds out general conditions for the operating characteristic of an item response category to provide a unique maximum likelihood…

  15. Fitting the Mixed Rasch Model to a Reading Comprehension Test: Identifying Reader Types

    ERIC Educational Resources Information Center

    Baghaei, Purya; Carstensen, Claus H.

    2013-01-01

    Standard unidimensional Rasch models assume that persons with the same ability parameters are comparable. That is, the same interpretation applies to persons with identical ability estimates as regards the underlying mental processes triggered by the test. However, research in cognitive psychology shows that persons at the same trait level may…

  16. Demonstrating Construct Validity of the American Board of Physical Medicine and Rehabilitation Part I Examination: An Analysis of Dimensionality.

    PubMed

    Raddatz, Mikaela M; Robinson, Lawrence R

    2017-02-16

    Ideally, high-stakes examinations assess 1 dimension of medical knowledge to produce precise estimates of a candidate's performance. It has not been reported whether the American Board of Physical Medicine and Rehabilitation Part 1 Certification Examination (ABPMR-CE-1) is unidimensional or not. To examine the ABPMR-CE-1 to measure how many dimensions it assesses. Retrospective observational study. We assessed examination results from the 2015 ABPMR-CE-1. A total of 489 deidentified candidates taking the 2015 ABPMR-CE-1. A 1-parameter Item Response Theory (IRT) measurement model was utilized. A Principal Components Analysis (PCA) of standardized residual correlations was used to detect multidimensionality. Number of primary dimensions reflected in the 325 test questions. The results of the dimensionality analysis indicated that the ABPMR-CE-1 examination is highly unidimensional from a psychometric perspective. Expert content review of the substantive content of small contrasting clusters of questions provided additional assurance of the unidimensional nature of the examination. The ABPMR-CE-1 appears indeed to measure a single construct, which suggests a sound structure of the examination. It closely approximates the assumption of statistical unidimensionality. To be determined. Copyright © 2017 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  17. Daring to Care: The Role of Culturally Relevant Care in Mentoring Black and Latino Male High School Students

    ERIC Educational Resources Information Center

    Watson, Wanda; Sealey-Ruiz, Yolanda; Jackson, Iesha

    2016-01-01

    This study seeks to challenge the uni-dimensional way care in school is written about by highlighting an often overlooked aspect of care--the kind that students do for each other. Data is drawn from focus groups conducted with the youth participants and founder of Umoja Network for Young Men (UMOJA), an all-male, school-based mentoring program for…

  18. Implications of Contemporary Intelligence Theories to Marketing Education

    ERIC Educational Resources Information Center

    Muncy, James A.

    2006-01-01

    In recent years, prominent psychologists have redefined intelligence to refer to one's ability to successfully perform within a sociocultural context. They have also questioned the historical unidimensional conceptualization of intelligence. In this article, the author briefly reviews the history of intelligence research to this point then…

  19. What Does the Just World Scale Measure: Dimension or Style?

    ERIC Educational Resources Information Center

    Ellard, John H.; Lerner, Melvin J.

    Rubin and Peplau's Just World Scale is based on the belief that a just world is a unidimensional construct in which individual beliefs are polarized according to immanent justice or ultimate justice. To investigate the effect of personal style on just world view, 109 male and female college students (who previously had completed the Just World…

  20. Impact of Violation of the Missing-at-Random Assumption on Full-Information Maximum Likelihood Method in Multidimensional Adaptive Testing

    ERIC Educational Resources Information Center

    Han, Kyung T.; Guo, Fanmin

    2014-01-01

    The full-information maximum likelihood (FIML) method makes it possible to estimate and analyze structural equation models (SEM) even when data are partially missing, enabling incomplete data to contribute to model estimation. The cornerstone of FIML is the missing-at-random (MAR) assumption. In (unidimensional) computerized adaptive testing…

  1. Technical Analysis of Teacher Responses to the Self-Evaluation Scale-Teacher (SES-T) Version

    ERIC Educational Resources Information Center

    Erford, Bradley T.; Lowe, Samantha; Chang, Catherine Y.

    2011-01-01

    The Self-Evaluation Scale--Teacher version, used to assess teacher perceived self-esteem of students, was analyzed. A unidimensional model emerged from exploratory factor analysis, with cautious acceptance of data fit. Reliability and external aspects of validity were supported by the Self-Evaluation Scale--Teacher data.

  2. Using Perceived Health to Test the Construct-Related Validity of Global Quality of Life

    ERIC Educational Resources Information Center

    Beckie, Theresa M.; Hayduk, Leslie A.

    2004-01-01

    Quality of life (QOL) is considered as a global, yet unidimensional, subjective assessment of one's satisfaction with life. We examine the construct validity of the available indicators of global QOL by constructing a causal model in which QOL is viewed as causally responding to several dimensions of perceived health. Global QOL is measured with…

  3. Concurrent Adaptive Measurement of Multiple Abilities.

    ERIC Educational Resources Information Center

    Ackerman, Terry A.; Davey, Tim C.

    An adaptive test can usually match or exceed the measurement precision of conventional tests several times its length. This increased efficiency is not without costs, however, as the models underlying adaptive testing make strong assumptions about examinees and items. Most troublesome is the assumption that item pools are unidimensional. Truly…

  4. Integration of Impulsivity and Positive Mood to Predict Risky Behavior: Development and Validation of a Measure of Positive Urgency

    ERIC Educational Resources Information Center

    Cyders, Melissa A.; Smith, Gregory T.; Spillane, Nichea S.; Fischer, Sarah; Annus, Agnes M.; Peterson, Claire

    2007-01-01

    In 3 studies, the authors developed and began to validate a measure of the propensity to act rashly in response to positive affective states (positive urgency). In Study 1, they developed a content-valid 14-item scale, showed that the measure was unidimensional, and showed that positive urgency was distinct from impulsivity-like constructs…

  5. Evaluation of Weighted Scale Reliability and Criterion Validity: A Latent Variable Modeling Approach

    ERIC Educational Resources Information Center

    Raykov, Tenko

    2007-01-01

    A method is outlined for evaluating the reliability and criterion validity of weighted scales based on sets of unidimensional measures. The approach is developed within the framework of latent variable modeling methodology and is useful for point and interval estimation of these measurement quality coefficients in counseling and education…

  6. Validity of the Beck Depression Inventory with Eating Disorder Patients.

    ERIC Educational Resources Information Center

    Pulos, Steven

    1996-01-01

    The factor structure of the Beck Depression Inventory (BDI) was studied with a subsample of 93 bulimic women from a total sample of 110 women with eating disorders. Results suggested that the BDI appears to assess a unidimensional construct in patients with eating disorders. (SLD)

  7. Bayesian Multidimensional IRT Models with a Hierarchical Structure

    ERIC Educational Resources Information Center

    Sheng, Yanyan; Wikle, Christopher K.

    2008-01-01

    As item response models gain increased popularity in large-scale educational and measurement testing situations, many studies have been conducted on the development and applications of unidimensional and multidimensional models. Recently, attention has been paid to IRT-based models with an overall ability dimension underlying several ability…

  8. Model-Based Collaborative Filtering Analysis of Student Response Data: Machine-Learning Item Response Theory

    ERIC Educational Resources Information Center

    Bergner, Yoav; Droschler, Stefan; Kortemeyer, Gerd; Rayyan, Saif; Seaton, Daniel; Pritchard, David E.

    2012-01-01

    We apply collaborative filtering (CF) to dichotomously scored student response data (right, wrong, or no interaction), finding optimal parameters for each student and item based on cross-validated prediction accuracy. The approach is naturally suited to comparing different models, both unidimensional and multidimensional in ability, including a…

  9. Child's Positive and Negative Impacts on Parents--A Person-Oriented Approach to Understanding Temperament in Preschool Children with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Bostrom, P. K.; Broberg, M.; Bodin, L.

    2011-01-01

    Background: Despite previous efforts to understand temperament in children with intellectual disability (ID), and how child temperament may affect parents, the approach has so far been unidimensional. Child temperament has been considered in relation to diagnosis, with the inherent risk of overlooking individual variation of children's temperament…

  10. Toward a Descriptive Science of Teaching: How the TDOP Illuminates the Multidimensional Nature of Active Learning in Postsecondary Classrooms

    ERIC Educational Resources Information Center

    Hora, Matthew T.

    2015-01-01

    Detailed accounts of teaching can shed light on the nature and prevalence of active learning, yet common approaches reduce teaching to unidimensional descriptors or binary categorizations. In this paper, I use the instructional systems-of-practice framework and the Teaching Dimensions Observation Protocol (TDOP) to advance an approach to thinking…

  11. Identifying Country-Specific Cultures of Physics Education: A Differential Item Functioning Approach

    ERIC Educational Resources Information Center

    Mesic, Vanes

    2012-01-01

    In international large-scale assessments of educational outcomes, student achievement is often represented by unidimensional constructs. This approach allows for drawing general conclusions about country rankings with respect to the given achievement measure, but it typically does not provide specific diagnostic information which is necessary for…

  12. A Binary Programming Approach to Automated Test Assembly for Cognitive Diagnosis Models

    ERIC Educational Resources Information Center

    Finkelman, Matthew D.; Kim, Wonsuk; Roussos, Louis; Verschoor, Angela

    2010-01-01

    Automated test assembly (ATA) has been an area of prolific psychometric research. Although ATA methodology is well developed for unidimensional models, its application alongside cognitive diagnosis models (CDMs) is a burgeoning topic. Two suggested procedures for combining ATA and CDMs are to maximize the cognitive diagnostic index and to use a…

  13. Fitting the Mixed Rasch Model to a Reading Comprehension Test: Identifying Reader Types

    ERIC Educational Resources Information Center

    Baghaei, Purya; Carstensen, Claus H.

    2013-01-01

    Standard unidimensional Rasch models assume that persons with the same ability parameters are comparable. That is, the same interpretation applies to persons with identical ability estimates as regards the underlying mental processes triggered by the test. However, research in cognitive psychology shows that persons at the same trait level may…

  14. Creating a Desirable Education System.

    ERIC Educational Resources Information Center

    Theobald, Robert

    The basic purpose of education is to prepare people to be successful in the world which will exist during their life span. Present day education is failing in this because our schools were organized for the industrial era. The resulting model requires that phenomena be predictable, understandable, and unidimensional. Today, we know that everything…

  15. The Log-Linear Cognitive Diagnostic Model (LCDM) as a Special Case of The General Diagnostic Model (GDM). Research Report. ETS RR-14-40

    ERIC Educational Resources Information Center

    von Davier, Matthias

    2014-01-01

    Diagnostic models combine multiple binary latent variables in an attempt to produce a latent structure that provides more information about test takers' performance than do unidimensional latent variable models. Recent developments in diagnostic modeling emphasize the possibility that multiple skills may interact in a conjunctive way within the…

  16. Analysis of Letter Name Knowledge Using Rasch Measurement

    ERIC Educational Resources Information Center

    Bowles, Ryan P.; Skibbe, Lori E.; Justice, Laura M.

    2011-01-01

    Letter name knowledge (LNK) is a key predictor of later reading ability and has been emphasized strongly in recent educational policy. Studies of LNK have implicitly treated it as a unidimensional construct with all letters equally relevant to its measurement. However, some empirical research suggests that contextual factors can affect the…

  17. Multigroup Generalizability Analysis of Verbal, Quantitative, and Nonverbal Ability Tests for Culturally and Linguistically Diverse Students

    ERIC Educational Resources Information Center

    Lakin, Joni M.; Lai, Emily R.

    2012-01-01

    For educators seeking to differentiate instruction, cognitive ability tests sampling multiple content domains, including verbal, quantitative, and nonverbal reasoning, provide superior information about student strengths and weaknesses compared with unidimensional reasoning measures. However, these ability tests have not been fully evaluated with…

  18. Latent Trait Theory Approach to Measuring Person-Organization Fit: Conceptual Rationale and Empirical Evaluation

    ERIC Educational Resources Information Center

    Chernyshenko, Oleksandr S.; Stark, Stephen; Williams, Alex

    2009-01-01

    The purpose of this article is to offer a new approach to measuring person-organization (P-O) fit, referred to here as "Latent fit." Respondents were administered unidimensional forced choice items and were asked to choose the statement in each pair that better reflected the correspondence between their values and those of the…

  19. Using the Advanced Progressive Matrices (Set I) to Assess Fluid Ability in a Short Time Frame: An Item Response Theory-Based Analysis

    ERIC Educational Resources Information Center

    Chiesi, Francesca; Ciancaleoni, Matteo; Galli, Silvia; Primi, Caterina

    2012-01-01

    This article is aimed at evaluating the possibility that Set I of the Advanced Progressive Matrices (APM-Set I) can be employed to assess fluid ability in a short time frame. The APM-Set I was administered to a sample of 1,389 primary and secondary school students. Confirmatory factor analysis attested to the unidimensionality of the scale. Item…

  20. Getting Alice through the door: social science research and natural resource management

    Treesearch

    Alan W. Ewert

    1995-01-01

    A number of trends are altering the role of science in natural resource management. These trends include the growing political power of science, the recognition that most natural resource problems are extremely complex and not prone to uni-dimensional solutions, and the increasing need to integrate an understanding of the human component into the planning and decision-...

  1. A Preliminary Study for a New Model of Sense of Community

    ERIC Educational Resources Information Center

    Tartaglia, Stefano

    2006-01-01

    Although Sense of Community (SOC) is usually defined as a multidimensional construct, most SOC scales are unidimensional. To reduce the split between theory and empirical research, the present work identifies a multifactor structure for the Italian Sense of Community Scale (ISCS) that has already been validated as a unitary index of SOC. This…

  2. The Analysis of a Construct That Does Not Exist: Misunderstanding the Multidimensional Nature of Trait Anxiety.

    ERIC Educational Resources Information Center

    Endler, Norman S.; Parker, James D. A.

    1990-01-01

    C. Davis and M. Cowles (1989) analyzed a total trait anxiety score on the Endler Multidimensional Anxiety Scales (EMAS)--a unidimensional construct that this multidimensional measure does not assess. Data are reanalyzed using the appropriate scoring procedure for the EMAS. Subjects included 145 undergraduates in 1 of 4 testing conditions. (SLD)

  3. Validity of the Strong Interest Inventory and Skills Confidence Inventory with Mexican American High School Students

    ERIC Educational Resources Information Center

    Flores, Lisa Y.; Spanierman, Lisa B.; Armstrong, Patrick Ian; Velez, Alexandra D.

    2006-01-01

    The structural and concurrent validity of the Strong Interest Inventory (SII) and Skills Confidence Inventory (SCI) was explored with a sample of 487 Mexican American high school students, and findings were compared with normative samples of the SII and SCI. Holland's (1997) structure was evaluated using circular unidimensional scaling. The…

  4. A Confirmatory Factor Analysis of the Life Orientation Test-Revised with Competitive Athletes

    ERIC Educational Resources Information Center

    Appaneal, Renee N.

    2012-01-01

    Current reviews outside of sport indicate that the Life Orientation Test-Revised (LOT-R) items load on two separate factors (optimism and pessimism) and, therefore, should be treated as independent constructs. However, researchers in the sport sciences continue to use the single composite score reflecting a unidimensional definition of optimism.…

  5. Measuring Adolescent Life Satisfaction: Psychometric Properties of the Satisfaction With Life Scale in a Sample of Italian Adolescents and Young Adults

    ERIC Educational Resources Information Center

    Di Fabio, Annamaria; Gori, Alessio

    2016-01-01

    This study examined the factor structure and the psychometric properties of the Satisfaction With Life Scale (SWLS) in a sample of 1,515 Italian (females = 60.26%, males = 39.74%) adolescents and young adults (M[subscript age] = 17.6 years, SD = 1.21). Results confirmed the unidimensionality, good reliability, and concurrent validity of the…

  6. A Revised Semantic Differential Scale Distinguishing between Negative and Positive God Images

    ERIC Educational Resources Information Center

    Francis, Leslie J.; Robbins, Mandy; Gibson, Harry M.

    2006-01-01

    A sample of 755 school pupils between the ages of 11 and 18 years completed the Benson and Spilka semantic differential measure of God images. Factor analysis indicated the advantages of re-scoring the measure as an eight item unidimensional index, defining semantic space relating to God images ranging from negative affect to positive affect.…

  7. Dimensions, Patterns, and Personality Correlates of Drug Abuse in an Offender Population.

    ERIC Educational Resources Information Center

    Holland, Terrill R.

    1978-01-01

    Drug abuse scores from prisoners resulted in two factors describing lifetime use of cannabis versus opiates. Analysis of Minnesota Multiphasic Personality Inventory (MMPI) profiles versus drug abuse patterns indicated moderate, unidimensional relationship between variables. MMPI profiles of opiate users were similar to those identified in research…

  8. A Correlational Analysis of Test Anxiety and Response Time on a Computerized Adaptive Math Test among Seventh Grade Students by Gender

    ERIC Educational Resources Information Center

    Brom, Michael Wayde

    2016-01-01

    Studies have shown that test anxiety has become more prevalent since the adoption of the No Child Left Behind Act in 2001 and that test anxiety negatively affects student achievement. Early research viewed test anxiety as being a unidimensional construct; however, recent research has purported that test anxiety is a multidimensional construct.…

  9. A Correlational Analysis of Test Anxiety and Response Time on a Computerized Adaptive Math Test among Seventh Grade Students by Gender

    ERIC Educational Resources Information Center

    Brom, Michael Wayde

    2016-01-01

    Studies have shown that test anxiety has become more prevalent since the adoption of the No Child Left Behind Act in 2001 and that test anxiety negatively affects student achievement. Early research viewed test anxiety as being a unidimensional construct; however, recent research has purported that test anxiety is a multidimensional construct.…

  10. Androgyny Versus Gender Schema: A Comment on Bem's Gender Schema Theory.

    ERIC Educational Resources Information Center

    Spence, Janet T.; Helmreich, Robert L.

    1981-01-01

    A logical contradiction in Bem's (1981) theory is outlined. The Bem Sex Role Inventory cannot measure a unidimensional construct, gender schema, and two independent constructs--masculinity and femininity. Such instruments measure self-images of instrumental and expressive personality traits which show little relationship to the constructs…

  11. Sequential Dependencies in Categorical Judgments of Radiographic Images

    ERIC Educational Resources Information Center

    Beckstead, Jason W.; Boutis, Kathy; Pecaric, Martin; Pusic, Martin V.

    2017-01-01

    Sequential context effects, the psychological interactions occurring between the events of successive trials when a sequence of similar stimuli are judged, have interested psychologists for decades. It has been well established that individuals exhibit sequential context effects in psychophysical experiments involving unidimensional stimuli.…

  12. Ramsay Curve IRT for Likert-Type Data

    ERIC Educational Resources Information Center

    Woods, Carol M.

    2007-01-01

    Ramsay curve item response theory (RC-IRT) was recently developed to detect and correct for nonnormal latent variables when unidimensional IRT models are fitted to data using maximum marginal likelihood estimation. The purpose of this research is to evaluate the performance of RC-IRT for Likert-type item responses with varying test lengths, sample…

  13. Conditional Covariance-Based Subtest Selection for DIMTEST

    ERIC Educational Resources Information Center

    Froelich, Amy G.; Habing, Brian

    2008-01-01

    DIMTEST is a nonparametric hypothesis-testing procedure designed to test the assumptions of a unidimensional and locally independent item response theory model. Several previous Monte Carlo studies have found that using linear factor analysis to select the assessment subtest for DIMTEST results in a moderate to severe loss of power when the exam…

  14. Three Approaches to Determining the Dimensionality of Binary Items.

    ERIC Educational Resources Information Center

    Roznowski, Mary; And Others

    1991-01-01

    Three heuristic methods of assessing the dimensionality of binary item pools were evaluated in a Monte Carlo investigation. The indices were based on (1) the local independence of unidimensional tests; (2) patterns of second-factor loadings derived from simplex theory; and (3) the shape of the curve of successive eigenvalues. (SLD)

  15. Using the Advanced Progressive Matrices (Set I) to Assess Fluid Ability in a Short Time Frame: An Item Response Theory-Based Analysis

    ERIC Educational Resources Information Center

    Chiesi, Francesca; Ciancaleoni, Matteo; Galli, Silvia; Primi, Caterina

    2012-01-01

    This article is aimed at evaluating the possibility that Set I of the Advanced Progressive Matrices (APM-Set I) can be employed to assess fluid ability in a short time frame. The APM-Set I was administered to a sample of 1,389 primary and secondary school students. Confirmatory factor analysis attested to the unidimensionality of the scale. Item…

  16. A Model-Free Diagnostic for Single-Peakedness of Item Responses Using Ordered Conditional Means

    ERIC Educational Resources Information Center

    Polak, Marike; De Rooij, Mark; Heiser, Willem J.

    2012-01-01

    In this article we propose a model-free diagnostic for single-peakedness (unimodality) of item responses. Presuming a unidimensional unfolding scale and a given item ordering, we approximate item response functions of all items based on ordered conditional means (OCM). The proposed OCM methodology is based on Thurstone & Chave's (1929) "criterion…

  17. Knowledge Contribution in Virtual Communities: Accounting for Multiple Dimensions of Social Presence through Social Identity

    ERIC Educational Resources Information Center

    Shen, Kathy Ning; Yu, Angela Yan; Khalifa, Mohamed

    2010-01-01

    Integrating social presence theory and social identity theory, this study brings system design and social influence aspects together to explain their joint effects on knowledge contribution in virtual communities (VCs). Different from most prior information systems (IS) research that adopts a uni-dimensional approach and restricts social presence…

  18. Measuring Trait Communication Apprehension: A Test of Rival Measurement Models of the PRCA-24.

    ERIC Educational Resources Information Center

    Levine, Timothy R.; McCroskey, James C.

    1990-01-01

    Tests three rival measurement models of a common measure of trait communication apprehension, the Personal Report of Communication Apprehension (PRCA-24). Finds that the second-order factor model better fits the data in terms of conceptual implications, psychometric properties, and empirical evidence than the linear, unidimensional model or the…

  19. How Should Discrepancy Be Assessed in Perfectionism Research? A Psychometric Analysis and Proposed Refinement of the Almost Perfect Scale-Revised

    ERIC Educational Resources Information Center

    Flett, Gordon L.; Mara, Constance A.; Hewitt, Paul L.; Sirois, Fuschia; Molnar, Danielle S.

    2016-01-01

    Research on perfectionism with the Almost Perfect Scale-Revised (APS-R) distinguishes adaptive perfectionists versus maladaptive perfectionists based primarily on their responses to the 12-item unidimensional APS-R Discrepancy subscale, which assesses the sense of falling short of standards. People described as adaptive perfectionists have high…

  20. A Factor-Analytic Comparison of Two Measures of Masculinity-Femininity in Post and Early Adolescent Populations.

    ERIC Educational Resources Information Center

    Mills, Carol J.

    Many researchers have questioned the validity of the underlying assumptions, the psychometric properties, and conceptualizations for both the older and new measures that generate two independent scores for masculinity and femininity. The assumptions of bipolarity and unidimensionality and the construct validity of existing masculinity/femininity…

  1. A Test of the Dimensionality Assumptions of Rotter's Internal-External Scale

    ERIC Educational Resources Information Center

    Klockars, Alan J.; Varnum, Susan W.

    1975-01-01

    Examined two assumptions about the dimensionality of Rotters' Internal-External (I-E) scale: First, the bipolarity of the two statements within each item pair; second, the unidimensionality of the overall construct. Both assumptions regarding Rotters' I-E Scale were found untenable. (Author/BJG)

  2. Development and Application of a New Approach to Testing the Bipolarity of Semantic Differential Items.

    ERIC Educational Resources Information Center

    Cogliser, Claudia C.; Schriesheim, Chester A.

    1994-01-01

    A method of testing semantic differential scales for bipolarity is developed using a new conception of bipolarity that does not require unidimensionality. Assessment of Fielder's Least Preferred Coworker instrument with 63 college student subjects using multidimensional scaling revealed its significant departures from bipolarity. (SLD)

  3. The Motivation of Stereotypic and Repetitive Behavior: Examination of Construct Validity of the Motivation Assessment Scale

    ERIC Educational Resources Information Center

    Joosten, Annette V.; Bundy, Anita C.

    2008-01-01

    Construct validity of the Motivation Assessment Scale (MAS) (Durand, Crimmins, The Motivation Assessment Scale 1988) was studied using Rasch analysis data from 67 children (246 MASs), with dual diagnosis of autism and intellectual disability or with intellectual disability only. Results failed to support the proposed unidimensional construct or…

  4. A Confirmatory Factor Analysis of the Life Orientation Test-Revised with Competitive Athletes

    ERIC Educational Resources Information Center

    Appaneal, Renee N.

    2012-01-01

    Current reviews outside of sport indicate that the Life Orientation Test-Revised (LOT-R) items load on two separate factors (optimism and pessimism) and, therefore, should be treated as independent constructs. However, researchers in the sport sciences continue to use the single composite score reflecting a unidimensional definition of optimism.…

  5. A Comparison of Responses on the Attitudes toward Women Scale and Attitudes toward Feminism Scale: Is There a Difference between College-Age and Later-Life Adults with the Original Norms?

    ERIC Educational Resources Information Center

    Byrne, Zinta S.; Felker, Sydney; Vacha-Haase, Tammi; Rickard, Kathryn M.

    2011-01-01

    Responses from college-age students and those 50 years and older were compared using the Attitudes Toward Women Scale and the Attitudes Toward Feminism Scale. Results from a multigroup confirmatory factor analysis showed groups differed on each scale, suggesting unidimensional scales no longer represent attitudes toward women or feminism.…

  6. AHIMSA - Ad hoc histogram information measure sensing algorithm for feature selection in the context of histogram inspired clustering techniques

    NASA Technical Reports Server (NTRS)

    Dasarathy, B. V.

    1976-01-01

    An algorithm is proposed for dimensionality reduction in the context of clustering techniques based on histogram analysis. The approach is based on an evaluation of the hills and valleys in the unidimensional histograms along the different features and provides an economical means of assessing the significance of the features in a nonparametric unsupervised data environment. The method has relevance to remote sensing applications.

  7. Effect Size Measures for Differential Item Functioning in a Multidimensional IRT Model

    ERIC Educational Resources Information Center

    Suh, Youngsuk

    2016-01-01

    This study adapted an effect size measure used for studying differential item functioning (DIF) in unidimensional tests and extended the measure to multidimensional tests. Two effect size measures were considered in a multidimensional item response theory model: signed weighted P-difference and unsigned weighted P-difference. The performance of…

  8. Development and Psychometric Evaluation of the Personal Growth Initiative Scale-II

    ERIC Educational Resources Information Center

    Robitschek, Christine; Ashton, Matthew W.; Spering, Cynthia C.; Geiger, Nathaniel; Byers, Danielle; Schotts, G. Christian; Thoen, Megan A.

    2012-01-01

    The original Personal Growth Initiative Scale (PGIS; Robitschek, 1998) was unidimensional, despite theory identifying multiple components (e.g., cognition and behavior) of personal growth initiative (PGI). The present research developed a multidimensional measure of the complex process of PGI, while retaining the brief and psychometrically sound…

  9. Psychometric Properties of a Portuguese Version of the Subjective Happiness Scale

    ERIC Educational Resources Information Center

    Spagnoli, Paola; Caetano, Antonio; Silva, Ana

    2012-01-01

    The Subjective Happiness Scale (SHS) constitutes an instrument for assessing subjective happiness. This study aims to present the validation of the SHS in a Portuguese adult population. A large representative sample (1,017 participants), from five different age groups was considered. Configurational invariance of the unidimensional structure of…

  10. The Economic Benefits of Predicting Job Performance

    DTIC Science & Technology

    1989-09-01

    placement, and to be able to use a terminology that permits the consideration of both unidimensional and multidimensional test and criterion sets for...largely random. The reason for the relatively low assignment efficiency is the reliance on low job standart - for a high quality recruit population

  11. Mokken Scale Analysis Using Hierarchical Clustering Procedures

    ERIC Educational Resources Information Center

    van Abswoude, Alexandra A. H.; Vermunt, Jeroen K.; Hemker, Bas T.; van der Ark, L. Andries

    2004-01-01

    Mokken scale analysis (MSA) can be used to assess and build unidimensional scales from an item pool that is sensitive to multiple dimensions. These scales satisfy a set of scaling conditions, one of which follows from the model of monotone homogeneity. An important drawback of the MSA program is that the sequential item selection and scale…

  12. Easier Said than Done: Rejoinder on Sijtsma and on Green and Yang

    ERIC Educational Resources Information Center

    Davenport, Ernest C.; Davison, Mark L.; Liou, Pey-Yan; Love, Quintin U.

    2016-01-01

    The main points of Sijtsma and Green and Yang in Educational Measurement: Issues and Practice (34, 4) are that reliability, internal consistency, and unidimensionality are distinct and that Cronbach's alpha may be problematic. Neither of these assertions are at odds with Davenport, Davison, Liou, and Love in the same issue. However, many authors…

  13. Examining the Bifactor IRT Model for Vertical Scaling in K-12 Assessment

    ERIC Educational Resources Information Center

    Koepfler, James R.

    2012-01-01

    Over the past decade, educational policy trends have shifted to a focus on examining students' growth from kindergarten through twelfth grade (K-12). One way states can track students' growth is with a vertical scale. Presently, every state that uses a vertical scale bases the scale on a unidimensional IRT model. These models make a…

  14. Electrohydrodynamically driven large-area liquid ion sources

    DOEpatents

    Pregenzer, Arian L.

    1988-01-01

    A large-area liquid ion source comprises means for generating, over a large area of the surface of a liquid, an electric field of a strength sufficient to induce emission of ions from a large area of said liquid. Large areas in this context are those distinct from emitting areas in unidimensional emitters.

  15. Similarity, Separability, and the Triangle Inequality.

    ERIC Educational Resources Information Center

    Tversky, Amos; Gati, Itamar

    1982-01-01

    The coincidence hypothesis predicts that dissimilarity between objects that differ on two separable dimensions is larger than predicted from their unidimensional differences on the basis of triangle inequality and segmental additivity. The coincidence hypothesis was supported in two-dimensional stimuli studies. (Author/CM)

  16. On the Value of Homogeneous Constructs for Construct Validation, Theory Testing, and the Description of Psychopathology

    ERIC Educational Resources Information Center

    Smith, Gregory T.; McCarthy, Denis M.; Zapolski, Tamika C. B.

    2009-01-01

    The authors argue for a significant shift in how clinical psychology researchers conduct construct validation and theory validation tests. They argue that sound theory and validation tests can best be conducted on measures of unidimensional or homogeneous constructs. Hierarchical organizations of such constructs are useful descriptively and…

  17. Development of an Instrument to Measure Staff-Reported Resident-to-Resident Elder Mistreatment (R-REM) Using Item Response Theory and Other Latent Variable Models

    PubMed Central

    Ramirez, Mildred

    2014-01-01

    Objectives: Although numerous studies have measured behaviors among individuals in congregate settings, few have focused on resident-to-resident elder mistreatment (R-REM). To our knowledge, there is no psychometrically developed measure of R-REM extant. The quantitative development of a measure of staff-reported R-REM is described. Methods: The design was a prevalent cohort study of residents of 5 long-term care facilities. The primary certified nursing assistant was interviewed about R-REM. Advanced measurement methods were used to develop a measure of R-REM. Results: The loadings on the general factor for the final 11-item scale were greater than those on the group factor except for the item “other physical behavior” (0.63 vs. 0.74), suggesting essential unidimensionality. Although the bifactor model fit was slightly better than that of the unidimensional model, the difference was trivial (bifactor comparative fit index [CFI] = 0.997, root mean square error of approximation [RMSEA] = 0.013, unidimensional CFI = 0.979, and RMSEA = 0.030). However, modest support was provided for use of verbal and physical subscales. The explained common variance statistics were 0.76 for the bifactor model compared with 0.63 for the unidimensional model. Discussion: The development of this R-REM measure will help to advance the measurement and ultimately evaluation of interventions associated with this important and under recognized problem facing residents in long-term care settings. PMID:23448960

  18. A Note on the Invariance of the DINA Model Parameters

    ERIC Educational Resources Information Center

    de la Torre, Jimmy; Lee, Young-Sun

    2010-01-01

    Cognitive diagnosis models (CDMs), as alternative approaches to unidimensional item response models, have received increasing attention in recent years. CDMs are developed for the purpose of identifying the mastery or nonmastery of multiple fine-grained attributes or skills required for solving problems in a domain. For CDMs to receive wider use,…

  19. Measuring Kindness at School: Psychometric Properties of a School Kindness Scale for Children and Adolescents

    ERIC Educational Resources Information Center

    Binfet, John Tyler; Gadermann, Anne M.; Schonert-Reichl, Kimberly A.

    2016-01-01

    In this study, we sought to create and validate a brief measure to assess students' perceptions of kindness in school. Participants included 1,753 students in Grades 4 to 8 attending public schools in a large school district in southern British Columbia. The School Kindness Scale (SKS) demonstrated a unidimensional factor structure and adequate…

  20. Graded Response Model Based on the Logistic Positive Exponent Family of Models for Dichotomous Responses

    ERIC Educational Resources Information Center

    Samejima, Fumiko

    2008-01-01

    Samejima ("Psychometrika "65:319--335, 2000) proposed the logistic positive exponent family of models (LPEF) for dichotomous responses in the unidimensional latent space. The objective of the present paper is to propose and discuss a graded response model that is expanded from the LPEF, in the context of item response theory (IRT). This…

  1. Daring to Care: The Role of Culturally Relevant Care in Mentoring Black and Latino Male High School Students

    ERIC Educational Resources Information Center

    Watson, Wanda; Sealey-Ruiz, Yolanda; Jackson, Iesha

    2016-01-01

    This study seeks to challenge the uni-dimensional way care in school is written about by highlighting an often overlooked aspect of care--the kind that students do for each other. Data is drawn from focus groups conducted with the youth participants and founder of Umoja Network for Young Men (UMOJA), an all-male, school-based mentoring program for…

  2. Comparing Categorization Models

    ERIC Educational Resources Information Center

    Rouder, Jeffrey N.; Ratcliff, Roger

    2004-01-01

    Four experiments are presented that competitively test rule- and exemplar-based models of human categorization behavior. Participants classified stimuli that varied on a unidimensional axis into 2 categories. The stimuli did not consistently belong to a category; instead, they were probabilistically assigned. By manipulating these assignment…

  3. Sustainable Communities: A Lens for Envisioning and Achieving a Community-Based Culture of Social and Ecological Peace

    ERIC Educational Resources Information Center

    Verhagen, Frans C.

    2014-01-01

    One of the obstacles to dealing with the social and ecological crises that obstruct the achievement of a culture of peace is silo thinking in global governance. A unidimensional mode of planning, silo thinking leads to decisions based on the area of expertise of a particular agency or intergovernmental organization and fails to recognize linkages…

  4. Implications of Contemporary Intelligence Theories to Marketing Education

    ERIC Educational Resources Information Center

    Muncy, James A.

    2006-01-01

    In recent years, prominent psychologists have redefined intelligence to refer to one's ability to successfully perform within a sociocultural context. They have also questioned the historical unidimensional conceptualization of intelligence. In this article, the author briefly reviews the history of intelligence research to this point then…

  5. The Dimensionality of Student Ratings of Teaching: Integration of Uni- and Multidimensional Models

    ERIC Educational Resources Information Center

    Apodaca, Pedro; Grad, Hector

    2005-01-01

    The debate on the unidimensionality versus multidimensionality of students' ratings of teaching performance, and the relationship of this dilemma to summative and formative uses of these instruments is reviewed, with special attention to the implications of their development and application in the Spanish university system. A comprehensive…

  6. An Extension of the Two-Parameter Logistic Model to the Multidimensional Latent Space.

    ERIC Educational Resources Information Center

    McKinley, Robert L.; Reckase, Mark D.

    Item response theory (IRT) has proven to be a very powerful and useful measurement tool. However, most of the IRT models that have been proposed, and all of the models commonly used, require the assumption of unidimensionality, which prevents their application to a wide range of tests. The few models that have been proposed for use with…

  7. Ramsay-Curve Item Response Theory for the Three-Parameter Logistic Item Response Model

    ERIC Educational Resources Information Center

    Woods, Carol M.

    2008-01-01

    In Ramsay-curve item response theory (RC-IRT), the latent variable distribution is estimated simultaneously with the item parameters of a unidimensional item response model using marginal maximum likelihood estimation. This study evaluates RC-IRT for the three-parameter logistic (3PL) model with comparisons to the normal model and to the empirical…

  8. Investigating the Hierarchical Factor Structure of the Fifth Edition of the 16PF: An Application of the Schmid-Leiman Orthogonalization Procedure.

    ERIC Educational Resources Information Center

    Chernyshenko, Oleksandr S.; Stark, Stephen; Chan, Kim Yin

    2001-01-01

    Studied the unidimensionality of the 16 noncognitive scales of the Sixteen Personality Factor Questionnaire (16PF) and the hierarchical factor structure of the inventory. Results using the Schmid Leiman orthogonalization procedure (J. Schmid and J. Leiman, 1957) showed that the noncognitive multi-item composites could be factored into 16…

  9. Measuring Interpersonal Callousness in Boys from Childhood to Adolescence: An Examination of Longitudinal Invariance and Temporal Stability

    ERIC Educational Resources Information Center

    Obradovic, Jelena; Pardini, Dustin A.; Long, Jeffrey D.; Loeber, Rolf

    2007-01-01

    Studies show interpersonal callousness (IC) plays an important role in understanding persistent antisocial behaviors; however, it remains unclear whether IC is a unidimensional construct, represented by invariant behavioral indexes and stable across different developmental periods. This study explores the structure and stability of IC using parent…

  10. Validation of an Instrument To Measure Dental Students' Use of, Knowledge about, and Attitudes towards Computers.

    ERIC Educational Resources Information Center

    Schleyer, Titus K. L.; Torres-Urquidy, Humberto; Straja, Sorin

    2001-01-01

    Conducted a measurement study to validate a preliminary survey for dental students which contained five subscales: computer use, information resource use, computer knowledge, capabilities of computer systems, and effects of computers on dental practice. Found that all survey scales except computer use were unidimensional; computer use required a…

  11. Career Decision Self-Efficacy Scale-Short Form: A Rasch Analysis of the Portuguese Version

    ERIC Educational Resources Information Center

    Miguel, Jose P.; Silva, Jose T.; Prieto, Gerardo

    2013-01-01

    The present study analyzes the psychometric properties of the Career Decision Self-Efficacy Scale-Short Form (CDSE-SF) in a sample of Portuguese secondary education students using the Rasch model. The results indicate that the 25 items of the CDSE-SF are well fitted to a latent unidimensional structure, as required by Rasch modeling. The response…

  12. Assessing Peer Victimization across Adolescence: Measurement Invariance and Developmental Change

    ERIC Educational Resources Information Center

    Rosen, Lisa H.; Beron, Kurt J.; Underwood, Marion K.

    2013-01-01

    An upward extension of the Revised Social Experience Questionnaire (Paquette & Underwood, 1999) was tested in a sample of adolescents followed longitudinally from 7th through 10th grade. We hypothesized that a 2-factor model with overt and social victimization factors would fit the data better than would a unidimensional model (a single…

  13. IRTPRO 2.1 for Windows (Item Response Theory for Patient-Reported Outcomes)

    ERIC Educational Resources Information Center

    Paek, Insu; Han, Kyung T.

    2013-01-01

    This article reviews a new item response theory (IRT) model estimation program, IRTPRO 2.1, for Windows that is capable of unidimensional and multidimensional IRT model estimation for existing and user-specified constrained IRT models for dichotomously and polytomously scored item response data. (Contains 1 figure and 2 notes.)

  14. Understanding Rasch Measurement: Understanding Resistance to the Data-model Relationship in Rasch's Paradigm: A Reflection for the Next Generation.

    ERIC Educational Resources Information Center

    Andrich, David

    2002-01-01

    Reflects on the development of the unidimensional Rasch model for ordered categories and the resistance to some of its initially counterintuitive implications, especially that the thresholds that partition the continuum to form the ordered categories can show an empirical problem with the data. (SLD)

  15. Determining the Representation of Constructed Response Items in Mixed-Item Format Exams.

    ERIC Educational Resources Information Center

    Sykes, Robert C.; Truskosky, Denise; White, Hillory

    The purpose of this research was to study the effect of the three different ways of increasing the number of points contributed by constructed response (CR) items on the reliability of test scores from mixed-item-format tests. The assumption of unidimensionality that underlies the accuracy of item response theory model-based standard error…

  16. Multiple-Group Noncompensatory Differential Item Functioning in Raju's Differential Functioning of Items and Tests

    ERIC Educational Resources Information Center

    Oshima, T. C.; Wright, Keith; White, Nick

    2015-01-01

    Raju, van der Linden, and Fleer (1995) introduced a framework for differential functioning of items and tests (DFIT) for unidimensional dichotomous models. Since then, DFIT has been shown to be a quite versatile framework as it can handle polytomous as well as multidimensional models both at the item and test levels. However, DFIT is still limited…

  17. A Comparison of Responses on the Attitudes toward Women Scale and Attitudes toward Feminism Scale: Is There a Difference between College-Age and Later-Life Adults with the Original Norms?

    ERIC Educational Resources Information Center

    Byrne, Zinta S.; Felker, Sydney; Vacha-Haase, Tammi; Rickard, Kathryn M.

    2011-01-01

    Responses from college-age students and those 50 years and older were compared using the Attitudes Toward Women Scale and the Attitudes Toward Feminism Scale. Results from a multigroup confirmatory factor analysis showed groups differed on each scale, suggesting unidimensional scales no longer represent attitudes toward women or feminism.…

  18. Semi-Nonparametric Methods for Detecting Latent Non-Normality: A Fusion of Latent Trait and Ordered Latent Class Modeling

    ERIC Educational Resources Information Center

    Schmitt, J. Eric; Mehta, Paras D.; Aggen, Steven H.; Kubarych, Thomas S.; Neale, Michael C.

    2006-01-01

    Ordered latent class analysis (OLCA) can be used to approximate unidimensional latent distributions. The main objective of this study is to evaluate the method of OLCA in detecting non-normality of an unobserved continuous variable (i.e., a common factor) used to explain the covariation between dichotomous item-level responses. Using simulation,…

  19. Perceived Organizational Support: Further Evidence of Construct Validity.

    ERIC Educational Resources Information Center

    Hutchison, Steven

    1997-01-01

    Confirmatory factor analysis was used to examine the construct validity of scores from the Survey of Perceived Organizational Support (SPOS)(R. Eisenberger and others, 1986) using responses of 205 college faculty and staff members. Consistent with previous research, the SPOS was found to be unidimensional and distinguishable from two similarly…

  20. GGUM2004: AWindows-Based Program to Estimate Parameters in the Generalized Graded Unfolding Model

    ERIC Educational Resources Information Center

    Roberts, James S.; Fang, Haw-ren

    2006-01-01

    The GGUM2004 computer program estimates parameters for a family of unidimensional unfolding item response theory (IRT) models. These unfolding IRT models predict higher item scores to the extent that a respondent is located close to an item on an underlying latent continuum. This prediction is often consistent with responses to traditional…

  1. A Minimum-Cost Network-Flow Solution to the Case v Thurstone Scaling Problem.

    ERIC Educational Resources Information Center

    Lattin, James M.

    1990-01-01

    An approach is presented for determining unidimensional scale estimates that are relatively insensitive to limited inconsistencies in paired comparisons data. The solution procedure--a minimum-cost network-flow problem--is presented in conjunction with a sensitivity diagnostic that assesses the influence of a single pairwise comparison on…

  2. A Model-Free Diagnostic for Single-Peakedness of Item Responses Using Ordered Conditional Means

    ERIC Educational Resources Information Center

    Polak, Marike; De Rooij, Mark; Heiser, Willem J.

    2012-01-01

    In this article we propose a model-free diagnostic for single-peakedness (unimodality) of item responses. Presuming a unidimensional unfolding scale and a given item ordering, we approximate item response functions of all items based on ordered conditional means (OCM). The proposed OCM methodology is based on Thurstone & Chave's (1929) "criterion…

  3. A Binary Programming Approach to Automated Test Assembly for Cognitive Diagnosis Models

    ERIC Educational Resources Information Center

    Finkelman, Matthew D.; Kim, Wonsuk; Roussos, Louis; Verschoor, Angela

    2010-01-01

    Automated test assembly (ATA) has been an area of prolific psychometric research. Although ATA methodology is well developed for unidimensional models, its application alongside cognitive diagnosis models (CDMs) is a burgeoning topic. Two suggested procedures for combining ATA and CDMs are to maximize the cognitive diagnostic index and to use a…

  4. Cognitive Correlates of Math Skills in Third-Grade Students

    ERIC Educational Resources Information Center

    Mannamaa, Mairi; Kikas, Eve; Peets, Katlin; Palu, Anu

    2012-01-01

    Math achievement is not a unidimensional construct but includes different skills that require different cognitive abilities. The focus of this study was to examine associations between a number of cognitive abilities and three domains of math skills (knowing, applying and problem solving) simultaneously in a multivariate framework. Participants…

  5. Multidimensional CAT Item Selection Methods for Domain Scores and Composite Scores: Theory and Applications

    ERIC Educational Resources Information Center

    Yao, Lihua

    2012-01-01

    Multidimensional computer adaptive testing (MCAT) can provide higher precision and reliability or reduce test length when compared with unidimensional CAT or with the paper-and-pencil test. This study compared five item selection procedures in the MCAT framework for both domain scores and overall scores through simulation by varying the structure…

  6. When Cognitive Diagnosis Meets Computerized Adaptive Testing: CD-CAT

    ERIC Educational Resources Information Center

    Cheng, Ying

    2009-01-01

    Computerized adaptive testing (CAT) is a mode of testing which enables more efficient and accurate recovery of one or more latent traits. Traditionally, CAT is built upon Item Response Theory (IRT) models that assume unidimensionality. However, the problem of how to build CAT upon latent class models (LCM) has not been investigated until recently,…

  7. Measurement Invariance versus Selection Invariance: Is Fair Selection Possible?

    ERIC Educational Resources Information Center

    Borsman, Denny; Romeijn, Jan-Willem; Wicherts, Jelte M.

    2008-01-01

    This article shows that measurement invariance (defined in terms of an invariant measurement model in different groups) is generally inconsistent with selection invariance (defined in terms of equal sensitivity and specificity across groups). In particular, when a unidimensional measurement instrument is used and group differences are present in…

  8. Application of the Bifactor Model to Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Seo, Dong Gi

    2011-01-01

    Most computerized adaptive tests (CAT) have been studied under the framework of unidimensional item response theory. However, many psychological variables are multidimensional and might benefit from using a multidimensional approach to CAT. In addition, a number of psychological variables (e.g., quality of life, depression) can be conceptualized…

  9. A Revised Semantic Differential Scale Distinguishing between Negative and Positive God Images

    ERIC Educational Resources Information Center

    Francis, Leslie J.; Robbins, Mandy; Gibson, Harry M.

    2006-01-01

    A sample of 755 school pupils between the ages of 11 and 18 years completed the Benson and Spilka semantic differential measure of God images. Factor analysis indicated the advantages of re-scoring the measure as an eight item unidimensional index, defining semantic space relating to God images ranging from negative affect to positive affect.…

  10. Measuring Adolescent Life Satisfaction: Psychometric Properties of the Satisfaction With Life Scale in a Sample of Italian Adolescents and Young Adults

    ERIC Educational Resources Information Center

    Di Fabio, Annamaria; Gori, Alessio

    2016-01-01

    This study examined the factor structure and the psychometric properties of the Satisfaction With Life Scale (SWLS) in a sample of 1,515 Italian (females = 60.26%, males = 39.74%) adolescents and young adults (M[subscript age] = 17.6 years, SD = 1.21). Results confirmed the unidimensionality, good reliability, and concurrent validity of the…

  11. Assessing Peer Victimization across Adolescence: Measurement Invariance and Developmental Change

    ERIC Educational Resources Information Center

    Rosen, Lisa H.; Beron, Kurt J.; Underwood, Marion K.

    2013-01-01

    An upward extension of the Revised Social Experience Questionnaire (Paquette & Underwood, 1999) was tested in a sample of adolescents followed longitudinally from 7th through 10th grade. We hypothesized that a 2-factor model with overt and social victimization factors would fit the data better than would a unidimensional model (a single…

  12. The Spectrum of School--University Partnerships: A Typology of Organizational Learning Systems

    ERIC Educational Resources Information Center

    Callahan, Jamie L.; Martin, Dorian

    2007-01-01

    School-university partnerships are not uni-dimensional projects. Success in these partnerships can be found in loosely-coupled systems such as client-server partnerships and in more tightly-coupled systems such as collaborative development centers. Using a comparative case study approach, we explore two school-university partnership case studies…

  13. Diversity Identity Development Training: Theory Informs Practice.

    ERIC Educational Resources Information Center

    Ramsey, MaryLou

    1996-01-01

    Most identity development models are unidimensional and mutually independent. They rarely acknowledge multiple cultural identifications or their relationship to diversity-awareness training. This article discusses this relationship in a four-stage conceptual model for diversity identity development and its implications for the design, structuring,…

  14. The Tenacious Goal Pursuit and Flexible Goal Adjustment Scales: Examination of Their Validity

    ERIC Educational Resources Information Center

    Mueller, Daniel J.; Kim, Kyung

    2004-01-01

    This study tested the unidimensionality of the Tenacious Goal Pursuit (TGP) and Flexible Goal Adjustment (FGA) scales and examined the relationships of the factors measured in these scales with two criterion constructs (happiness and self-acceptance) and with age in a sample 292 adults (ranging from 50 to 90 years). Confirmatory factor analyses…

  15. Some New Dimensions of Student Attitudes Toward Basic School Subjects.

    ERIC Educational Resources Information Center

    Hogan, Thomas P.

    To investigate whether student attitudes toward basic school subjects were multidimensional, responses of 876 students in grade 6 to a preliminary pool of 72 items from the Survey of School Attitudes (SSA) were factor analyzed. If attitudes are unidimensional, as suggested by the four scores yielded by the SSA (one each for reading/language arts,…

  16. An Interactive Multiobjective Programming Approach to Combinatorial Data Analysis.

    ERIC Educational Resources Information Center

    Brusco, Michael J.; Stahl, Stephanie

    2001-01-01

    Describes an interactive procedure for multiobjective asymmetric unidimensional seriation problems that uses a dynamic-programming algorithm to generate partially the efficient set of sequences for small to medium-sized problems and a multioperational heuristic to estimate the efficient set for larger problems. Applies the procedure to an…

  17. Psychometric Properties of Measures of Team Diversity with Likert Data

    ERIC Educational Resources Information Center

    Deng, Lifang; Marcoulides, George A.; Yuan, Ke-Hai

    2015-01-01

    Certain diversity among team members is beneficial to the growth of an organization. Multiple measures have been proposed to quantify diversity, although little is known about their psychometric properties. This article proposes several methods to evaluate the unidimensionality and reliability of three measures of diversity. To approximate the…

  18. Longitudinal Tests of Competing Factor Structures for the Rosenberg Self-Esteem Scale: Traits, Ephemeral Artifacts, and Stable Response Styles

    ERIC Educational Resources Information Center

    Marsh, Herbert W.; Scalas, L. Francesca; Nagengast, Benjamin

    2010-01-01

    Self-esteem, typically measured by the Rosenberg Self-Esteem Scale (RSE), is one of the most widely studied constructs in psychology. Nevertheless, there is broad agreement that a simple unidimensional factor model, consistent with the original design and typical application in applied research, does not provide an adequate explanation of RSE…

  19. Best Design for Multidimensional Computerized Adaptive Testing with the Bifactor Model

    ERIC Educational Resources Information Center

    Seo, Dong Gi; Weiss, David J.

    2015-01-01

    Most computerized adaptive tests (CATs) have been studied using the framework of unidimensional item response theory. However, many psychological variables are multidimensional and might benefit from using a multidimensional approach to CATs. This study investigated the accuracy, fidelity, and efficiency of a fully multidimensional CAT algorithm…

  20. Component Structure, Reliability, and Stability of Lawrence's Self-Esteem Questionnaire (LAWSEQ)

    ERIC Educational Resources Information Center

    Rae, Gordon; Dalto, Georgia; Loughrey, Dolores; Woods, Caroline

    2011-01-01

    Lawrence's Self-Esteem Questionnaire (LAWSEQ) was administered to 120 Year 1 pupils in six schools in Belfast, Northern Ireland. A principal components analysis indicated that the scale items were unidimensional and that the reliability of the scores, as estimated by Cronbach's alpha, was satisfactory ([alpha] = 0.73). There were no differences…

  1. Measurement Invariance versus Selection Invariance: Is Fair Selection Possible?

    ERIC Educational Resources Information Center

    Borsman, Denny; Romeijn, Jan-Willem; Wicherts, Jelte M.

    2008-01-01

    This article shows that measurement invariance (defined in terms of an invariant measurement model in different groups) is generally inconsistent with selection invariance (defined in terms of equal sensitivity and specificity across groups). In particular, when a unidimensional measurement instrument is used and group differences are present in…

  2. Satisfaction Ratings of QOLPAV: Psychometric Properties Based on the Graded Response Model

    ERIC Educational Resources Information Center

    Chen, Ssu-Kuang; Hwang, Fang-Ming; Lin, Sunny S. J.

    2013-01-01

    A scale measuring quality of life (QOL) is important in adolescent research. Using the graded response model (GRM), this study evaluates the psychometric properties of the satisfaction ratings of the Quality of Life Profile Adolescent Version (QOLPAV). Data for 1,392 adolescents were used to check IRT assumptions such as unidimensionality and…

  3. Dimensionality Analyses of the "GRE"® revised General Test Verbal and Quantitative Measures. ETS GRE® Board Research Report. ETS GRE®-16-02. ETS Research Report. RR-16-20

    ERIC Educational Resources Information Center

    Robin, Frédéric; Bejar, Isaac; Liang, Longjuan; Rijmen, Frank

    2016-01-01

    Exploratory and confirmatory factor analyses of domestic data from the" GRE"® revised General Test, introduced in 2011, were conducted separately for the verbal (VBL) and quantitative (QNT) reasoning measures to evaluate the unidimensionality and local independence assumptions required by item response theory (IRT). Results based on data…

  4. Checking the Appropriateness of Item Response Theory Models by Predicting the Distribution of Observed Scores: The Program EO-Fit.

    ERIC Educational Resources Information Center

    Ferrando, Pere J.; Lorenzo-Seva, Urbano

    2001-01-01

    Describes a Windows program for checking the suitability of unidimensional logistic item response models for binary and ordered polytomous responses with respect to a given set of data. The program is based on predicting the observed test score distributions from the item characteristic curves. (SLD)

  5. TH-SCORE: A Program for Obtaining Ability Estimates under Different Psychometric Models.

    ERIC Educational Resources Information Center

    Ferrando, Pere J.; Lorenzo, Urbano

    1998-01-01

    A program for obtaining ability estimates and their standard errors under a variety of psychometric models is documented. The general models considered are (1) classical test theory; (2) item factor analysis for continuous censored responses; and (3) unidimensional and multidimensional item response theory graded response models. (SLD)

  6. Development and Initial Validation of the Inventory of Microaggressions against Black Individuals

    ERIC Educational Resources Information Center

    Mercer, Sterett H.; Zeigler-Hill, Virgil; Wallace, Marion; Hayes, DeMarquis M.

    2011-01-01

    The present article describes the development and initial validation of the Inventory of Microaggressions Against Black Individuals (IMABI) using a sample of 385 undergraduates who self-identified as Black or African American. The IMABI is a 14-item, unidimensional measure of racial microaggressions that captures both microinsults and…

  7. Multidimensional Item Response Theory Models in Vocational Interest Measurement: An Illustration Using the AIST-R

    ERIC Educational Resources Information Center

    Wetzel, Eunike; Hell, Benedikt

    2014-01-01

    Vocational interest inventories are commonly analyzed using a unidimensional approach, that is, each subscale is analyzed separately. However, the theories on which these inventories are based often postulate specific relationships between the interest traits. This article presents a multidimensional approach to the analysis of vocational interest…

  8. Easier Said than Done: Rejoinder on Sijtsma and on Green and Yang

    ERIC Educational Resources Information Center

    Davenport, Ernest C.; Davison, Mark L.; Liou, Pey-Yan; Love, Quintin U.

    2016-01-01

    The main points of Sijtsma and Green and Yang in Educational Measurement: Issues and Practice (34, 4) are that reliability, internal consistency, and unidimensionality are distinct and that Cronbach's alpha may be problematic. Neither of these assertions are at odds with Davenport, Davison, Liou, and Love in the same issue. However, many authors…

  9. A Multiple Motives Approach to Tobacco Dependence: The Wisconsin Inventory of Smoking Dependence Motives (WISDM-68)

    ERIC Educational Resources Information Center

    Piper, Megan E.; Piasecki, Thomas M.; Federman, E. Belle; Bolt, Daniel M.; Smith, Stevens S.; Fiore, Michael C.; Baker, Timothy C.

    2004-01-01

    The dependence construct fills an important explanatory role in motivational accounts of smoking and relapse. Frequently used measures of dependence are either atheoretical or grounded in a unidimensional model of physical dependence. This research creates a multidimensional measure of dependence that is based on theoretically grounded motives for…

  10. Comparing Three Estimation Methods for the Three-Parameter Logistic IRT Model

    ERIC Educational Resources Information Center

    Lamsal, Sunil

    2015-01-01

    Different estimation procedures have been developed for the unidimensional three-parameter item response theory (IRT) model. These techniques include the marginal maximum likelihood estimation, the fully Bayesian estimation using Markov chain Monte Carlo simulation techniques, and the Metropolis-Hastings Robbin-Monro estimation. With each…

  11. Personality Correlates of Aggression: Evidence from Measures of the Five-Factor Model, UPPS Model of Impulsivity, and BIS/BAS

    ERIC Educational Resources Information Center

    Miller, Joshua D.; Zeichner, Amos; Wilson, Lauren F.

    2012-01-01

    Although many studies of personality and aggression focus on multidimensional traits and higher order personality disorders (e.g., psychopathy), lower order, unidimensional traits may provide more precision in identifying specific aspects of personality that relate to aggression. The current study includes a comprehensive measurement of lower…

  12. The Evidence for a Subscore Structure in a Test of English Language Competency for English Language Learners

    ERIC Educational Resources Information Center

    Reckase, Mark D.; Xu, Jing-Ru

    2015-01-01

    How to compute and report subscores for a test that was originally designed for reporting scores on a unidimensional scale has been a topic of interest in recent years. In the research reported here, we describe an application of multidimensional item response theory to identify a subscore structure in a test designed for reporting results using a…

  13. Some Issues in Item Response Theory: Dimensionality Assessment and Models for Guessing

    ERIC Educational Resources Information Center

    Smith, Jessalyn

    2009-01-01

    Currently, standardized tests are widely used as a method to measure how well schools and students meet academic standards. As a result, measurement issues have become an increasingly popular topic of study. Unidimensional item response models are used to model latent abilities and specific item characteristics. This class of models makes…

  14. Educational Mismatch of Graduates: A Multidimensional and Fuzzy Indicator

    ERIC Educational Resources Information Center

    Betti, Gianni; D'Agostino, Antonella; Neri, Laura

    2011-01-01

    In this paper we attempt to measure the educational mismatch, seen as a problem of overeducation, using a multidimensional and fuzzy methodology. Educational mismatch can be difficult to measure because many factors can converge to its definition and the traditional unidimensional indicators presented in literature can offer a restricted view of…

  15. The Development of a Hierarchical Polychotomous ADL-IADL Scale for Noninstitutionalized Elders.

    ERIC Educational Resources Information Center

    Kempen, G. I. J. M.; Suurmeijer, T. P. B. M.

    1990-01-01

    Tested hierarchical scale comprising 18 activities of daily living (ADL) and instrumental activities of daily living (IADL) items on 101 noninstitutionalized older adults in Netherlands. Results confirmed possibility of constructing unidimensional, hierarchical. polychotomous scale measuring "functional problems on ADL-IADL." Considered…

  16. How Should Discrepancy Be Assessed in Perfectionism Research? A Psychometric Analysis and Proposed Refinement of the Almost Perfect Scale-Revised

    ERIC Educational Resources Information Center

    Flett, Gordon L.; Mara, Constance A.; Hewitt, Paul L.; Sirois, Fuschia; Molnar, Danielle S.

    2016-01-01

    Research on perfectionism with the Almost Perfect Scale-Revised (APS-R) distinguishes adaptive perfectionists versus maladaptive perfectionists based primarily on their responses to the 12-item unidimensional APS-R Discrepancy subscale, which assesses the sense of falling short of standards. People described as adaptive perfectionists have high…

  17. Assessing Acquiescence in Surveys Using Positively and Negatively Worded Questions

    ERIC Educational Resources Information Center

    Hutton, Amy Christine

    2017-01-01

    The purpose of this study was to assess the impact of acquiescence on both positively and negatively worded questions, both when unidimensionality was assumed and when it was not. To accomplish this, undergraduate student responses to a previously validated survey of student engagement were used to compare several models of acquiescence, using a…

  18. Orthogonal Higher Order Factor Structure of the Stanford-Binet Intelligence Scales--Fifth Edition for Children and Adolescents

    ERIC Educational Resources Information Center

    Canivez, Gary L.

    2008-01-01

    Orthogonal higher-order factor structure of the Stanford-Binet Intelligence Scales-Fifth Edition (SB-5; Roid, 2003a) for child and adolescent samples is reported. Multiple criteria for factor extraction unanimously supported extraction of only one dimension and a unidimensional model. However, following results from DiStefano and Dombrowski (2006)…

  19. A Reliability Generalization Study on the Survey of Perceived Organizational Support: The Effects of Mean Age and Number of Items on Score Reliability

    ERIC Educational Resources Information Center

    Hellman, Chan M.; Fuqua, Dale R.; Worley, Jody

    2006-01-01

    The Survey of Perceived Organizational Support (SPOS) is a unidimensional measure of the general belief held by an employee that the organization is committed to him or her, values his or her continued membership, and is generally concerned about the employee's well-being. In the interest of efficiency, researchers are often compelled to use a…

  20. Longitudinal Tests of Competing Factor Structures for the Rosenberg Self-Esteem Scale: Traits, Ephemeral Artifacts, and Stable Response Styles

    ERIC Educational Resources Information Center

    Marsh, Herbert W.; Scalas, L. Francesca; Nagengast, Benjamin

    2010-01-01

    Self-esteem, typically measured by the Rosenberg Self-Esteem Scale (RSE), is one of the most widely studied constructs in psychology. Nevertheless, there is broad agreement that a simple unidimensional factor model, consistent with the original design and typical application in applied research, does not provide an adequate explanation of RSE…

  1. Construct Validity of Scores/Measures from a Developmental Assessment in Mathematics Using Classical and Many-Facet Rasch Measurement.

    ERIC Educational Resources Information Center

    Banerji, Madhabi

    2000-01-01

    Validated data from a developmental mathematics assessment using classical and three-faceted Rasch measurement methods. Analysis of field test data for 289 elementary school students suggested that a unidimensional construct was being measured, as defined by Rasch criteria. Discusses limitations in confirming content-related validity of the…

  2. The Factor Structure of the Work-Family Conflict Multidimensional Scale: Exploring the Expectations of College Students

    ERIC Educational Resources Information Center

    Gaffey, Abigail R.; Rottinghaus, Patrick J.

    2009-01-01

    Work-family conflict (WFC) has been examined from a unidimensional approach, yet recent research has revealed three types (i.e., time, strain, and behavior) and two directions of work-family conflict. Previous researchers suggested that college students are unable to discern between the multiple-facets of WFC, thus measured anticipated WFC…

  3. Tank binding kinase 1 is a centrosome-associated kinase necessary for microtubule dynamics and mitosis.

    PubMed

    Pillai, Smitha; Nguyen, Jonathan; Johnson, Joseph; Haura, Eric; Coppola, Domenico; Chellappan, Srikumar

    2015-12-10

    TANK Binding Kinase 1 (TBK1) is a non-canonical IκB kinase that contributes to KRAS-driven lung cancer. Here we report that TBK1 plays essential roles in mammalian cell division. Specifically, levels of active phospho-TBK1 increase during mitosis and localize to centrosomes, mitotic spindles and midbody, and selective inhibition or silencing of TBK1 triggers defects in spindle assembly and prevents mitotic progression. TBK1 binds to the centrosomal protein CEP170 and to the mitotic apparatus protein NuMA, and both CEP170 and NuMA are TBK1 substrates. Further, TBK1 is necessary for CEP170 centrosomal localization and binding to the microtubule depolymerase Kif2b, and for NuMA binding to dynein. Finally, selective disruption of the TBK1-CEP170 complex augments microtubule stability and triggers defects in mitosis, suggesting that TBK1 functions as a mitotic kinase necessary for microtubule dynamics and mitosis.

  4. Void Growth and Coalescence Simulations

    DTIC Science & Technology

    2013-08-01

    AFRL-RW-EG-TR-2013-080 VOID GROWTH AND COALESCENCE SIMULATIONS Derek J. Reding 1 Pavol Stofko 2 Robert J. Dorgan 3 Michael E. Nixon 4...3002 W0AQ Derek J. Reding 1 Pavol Stofko 2 Robert J. Dorgan 3 Michael E. Nixon 4 1 Jacobs TEAS Team; 1030 Titan Court; Fort Walton Beach, FL 32547...on Steady-State Fluid Flow and Heat Transfer," Journal of Fluids Engineering, vol. 125, no. 4, pp. 731-733, 2003. [19] D. J. Reding and S. Hanagud

  5. Acceleration of a Semi Implicit Non-hydrostatic Atmospheric Model on Many Core Architecture

    NASA Astrophysics Data System (ADS)

    Abdi, D. S.; Giraldo, F.; Wilcox, L.; Warburton, T.

    2016-12-01

    The Non-hydrostatic Unified Model of the Atmosphere (NUMA) uses high-order continuous and discontinuous Galerkin spatial discretization that result in high arithmetic intensity per-degree of freedom. Therefore, these methods are suitable for the future many-core and multi-core supercomputers with heterogeneous computing units. In our previous work, we have presented scalability of NUMA using explicit time integration that performed well on a GPU cluster. We achieved two orders of magnitude speedup over the CPU version of NUMA, while maintaining a 90% weak scaling efficiency using up to 16384 GPUs of the titan supercomputer. However, in operational numerical weather prediction, it is often necessary to use semi-implicit time integrators that allow for a much larger time step than explicit time integrators. A lot of machinery is required to enable semi-implcit time integration on the GPU and other accelerators. In this work, we will present the work on porting of the semi-implicit time integrators 1D and 3D IMEX, that require solving a system of linear equations at each time step. The scalability of the semi-implicit NUMA will be tested on supercomputers consisting of different accelerators such as CPUs, GPUs, KNL. The porting of NUMA to many-core architecture is done using a unified language called OCCA - that takes a `write once run everywhere' approach for different accelerators. To be able to scale well on future exa-scale supercomputers with heterogeneous accelerators, NUMA should be portable in-terms of both code and performance across different devices. The OCCA language's design is such that a node-per-thread approach is used on the GPU while an element-per-thread approach is used on the CPU. This makes OCCA highly performance portable and achieve results equalling that obtained with a native language (e.g. OpenMP or CUDA).

  6. The Use of a Human Breast Tumor Progression Series and a 3-D Culture Model to Determine if Nuclear Structure Could Provide a Molecular and Therapeutic Marker

    DTIC Science & Technology

    2000-01-01

    California REPORT NUMBER Ernest Orlando Lawrence Berkeley National Laboratory Berkeley, California 94720 E -MAIL: SLelievre @lbl.gov 9. SPONSORING...disorganized (cell clusters: S1-EGFR, T4-2) structures. Confocal fluorescence images (0.2 p optical sections) of NuMA (a-d) and collagen IV ( e -h...scheme under the images illustrates NuMA distribution (in gray). ( e -h) BM organization in S1-50, S1-EGFR, T4-2, and RT4 cells. Acini formed by S1-50

  7. Function of donor cell centrosome in intraspecies and interspecies nuclear transfer embryos

    SciTech Connect

    Zhong Zhisheng; Zhang Gang; Meng Xiaoqian; Zhang Yanling; Chen Dayuan; Schatten, Heide; Sun Qingyuan . E-mail: sunqy1@yahoo.com

    2005-05-15

    Centrosomes, the main microtubule-organizing centers (MTOCs) in most animal cells, are important for many cellular activities such as assembly of the mitotic spindle, establishment of cell polarity, and cell movement. In nuclear transfer (NT), MTOCs that are located at the poles of the meiotic spindle are removed from the recipient oocyte, while the centrosome of the donor cell is introduced. We used mouse MII oocytes as recipients, mouse fibroblasts, rat fibroblasts, or pig granulosa cells as donor cells to construct intraspecies and interspecies nuclear transfer embryos in order to observe centrosome dynamics and functions. Three antibodies against centrin, {gamma}-tubulin, and NuMA, respectively, were used to stain the centrosome. Centrin was not detected either at the poles of transient spindles or at the poles of first mitotic spindles. {gamma}-tubulin translocated into the two poles of the transient spindles, while no accumulated {gamma}-tubulin aggregates were detected in the area adjacent to the two pseudo-pronuclei. At first mitotic metaphase, {gamma}-tubulin was translocated to the spindle poles. The distribution of {gamma}-tubulin was similar in mouse intraspecies and rat-mouse interspecies embryos. The NuMA antibody that we used can recognize porcine but not murine NuMA protein, so it was used to trace the NuMA protein of donor cell in reconstructed embryos. In the pig-mouse interspecies reconstructed embryos, NuMA concentrated between the disarrayed chromosomes soon after activation and translocated to the transient spindle poles. NuMA then immigrated into pseudo-pronuclei. After pseudo-pronuclear envelope breakdown, NuMA was located between the chromosomes and then translocated to the spindle poles of first mitotic metaphase. {gamma}-tubulin antibody microinjection resulted in spindle disorganization and retardation of the first cell division. NuMA antibody microinjection also resulted in spindle disorganization. Our findings indicate that (1) the

  8. Astronomy, Art and Mythology in a Public Elementary School in Itaocara/rj. (Spanish Title: Astronomía, Arte y Mitologia en el Ensino Fundamental en Una Escuela de la Red Estatal en ITAOCARA/RJ.) Astronomia, Arte e Mitologia no Ensino Fundamental em Escola da Rede Estadual em ITAOCARA/RJ

    NASA Astrophysics Data System (ADS)

    Oliveira Bernardes, Adriana; Ramos dos Santos, Arleidimar

    2008-12-01

    Volunteer advisors at Itaocara Astronomy Club Marcos Pontes(CAIMP), in their majority high school students, introduced students at Teotônio Brandão Vilela Elementary School to basic concepts in Astronomy, Physics, and Mythology. Computer Science, Arts, puppetry, and educational videos were used to stimulate students to share their feelings and test their knowledge of the concepts presented. The work done by the volunteers helped boost the student's self-esteem and improved their oral skills by applying their knowledge of Physics and Astronomy in Lab experiments. The main goals of the CAIMP are the possibility of including astronomy in Elementary school curricula and developing an interdisciplinary work involving Astronomy, Arts, and Mythology. Through tests and reports, the students who participated in the Brazilian Astronomy Olympics, showed an increase in their knowldge of the sujects presented during the volunteer work. Durante el curso de un trabajo voluntario con estudiantes de nivel primario (1 º a 4 º grado), los guías de Astronomía miembros del CAIMP (Club de Astronomía de Itaocara "Marcos Puentes"), en su mayoría estudiantes secundarios, desarrollaron un trabajo de introducción a las Ciencias y Astronomía con alumnos del colegio estatal Teotônio Vilela Brandão. A través de talleres de informática, artes, videos educativos y teatro de títeres, los estudiantes pudieron expresar sus conocimientos y emociones frente a las leyendas mitológicas con las que se inició el trabajo de introducción. La labor desarrollada por los guías con los alumnos promovió la integración entre las aulas del colegio haciéndolos participar en actividades con el fin de estimular su expresión verbal y aumentar su autoestima. Trabajando diversas formas de expresión, los alumnos pudieron realizar experimentos y conocer algunos conceptos de Física y Astronomía al mismo tiempo que adquirían autonomía para la libre expresión de sus sentimientos y de los conocimientos recibidos. El trabajo en sí ha mostrado además de la posibilidad de la inclusión de la Astronomía en la Educación Primaria, la posibilidad de un trabajo interdisciplinario en los niveles iniciales incluyendo Astronomía, Arte y Mitología. Los resultados presentados por los estudiantes en las Olimpiadas promovidas en la escuela y por la OBA (Olimpiada Brasilera de Astronomía) permitieron verificar un creciente aprendizaje y estimulo hacia las materias científicas, comprobados por la apropiada expresión de los conceptos adquiridos de astronomía y presentados en evaluaciones o en informes obtenidos de ellos mismos, sus familias y profesores. Desenvolvendo um trabalho voluntário junto aos alunos do ensino fundamental no 1º ciclo (1ª a 4ª série), os monitores de Astronomia membros do CAIMP (Clube de Astronomia de Itaocara Marcos Pontes), que eram em sua maioria alunos do ensino médio, desenvolveram um trabalho de aproximação entre os alunos do Colégio Estadual Teotônio Brandão Vilela e os temas envolvendo Ciências e Astronomia. Através de oficinas de informática, artes, vídeos educativos e teatros de fantoches, os alunos puderam expressar seus conhecimentos e emoções diante das lendas mitológicas com as quais começaram a ter contato. O trabalho desenvolvido pelos monitores junto aos alunos proporcionou a integração entre as turmas do colégio e os levou a participação em atividades de maneira a estimular sua oralidade e aumentar sua auto-estima. Trabalhando várias formas de expressões, os alunos puderam realizar seus experimentos e conhecer alguns conceitos de Física e Astronomia, enquanto adquiriam autonomia para se expressarem de acordo com seus sentimentos e conhecimentos adquiridos. O trabalho em si mostrou além da possibilidade de inserção de Astronomia no Ensino Fundamental, a possibilidade de realização de um trabalho interdisciplinar nas séries iniciais envolvendo Astronomia, Arte e Mitologia. Os resultados apresentados pelos alunos nas Olimpíadas promovidas na escola e pela OBA (Olimpíada Brasileira de Astronomia) possibilitaram a verificação de uma crescente aprendizagem e estímulo ao conhecimento de temas científicos, que foi comprovado diante da apropriação dos conceitos de Astronomia adquiridos e apresentados em resultados como avaliações, ou ainda, diante dos relatos obtidos dos mesmos, suas famílias e professores.

  9. EPA Awards $400K in Brownfields Grants to Cleanup and Revitalize West Point, Mississippi

    EPA Pesticide Factsheets

    ATLANTA - Today, the U.S. Environmental Protection Agency (EPA) announced the selection of two new grant investments totaling $400,000 in West Point, Miss. These investments will provide the community with funding necessary to assess, clean and rede

  10. Hereditary Models for Airfoils in Unsteady Aerodynamics, Numerical Approximations and Parameter Estimation.

    DTIC Science & Technology

    1982-02-01

    delay" feature of a wing-tall configuration has been observed by Reding and Ericsson [ 14,15] in their stability malysis of the 747/Orbiter. To see...an Important (and limiting) consideration In numerical computations. Therefore, we seek sonie method to reduce this computational burdon. To modify...nonuniform lift theory to airplane dynamics, NACA TN 667, 1938. 14. J. P. Reding and L. E. Ericsson , Aeroelastic stability of the 747/Orbiter, J

  11. Army Sustainment. Volume 44, Issue 5. September-October 2012

    DTIC Science & Technology

    2012-10-01

    open up and ask for a dialog with the spouse or officer if they feel that something is not right. Social role play helps students work on...would walk through a detailed, lockstep framework of our rede - ployment support from start to finish and scrutinize any The 407th Brigade Support...Organizational Redeployment Around 11 March, we received an opportunity to rede - ploy C Company early since its mission was complete. We called C

  12. Paid to Perform: Aligning Total Military Compensation With Talent Management. Volume 8

    DTIC Science & Technology

    2015-06-01

    study upon which a wider compensation model can be built, we propose a system that thoughtfully integrates rede - signed basic pays and pensions...Taken together, these basic pay and pension rede - sign components will create a far more cost-effective total compensation system than the one...12, 2015, available from www. militarytimes.com/story/military/pentagon/2015/04/12/carter- social - media/25513773/. 12. While a myriad number of

  13. Lessons Learned From Joint Training Land Management

    DTIC Science & Technology

    2013-02-28

    address the environmental, social and economic aspects of conducting business. This process also includes procurement being considered as an integral part...elevation from approximately 240m to 450m above Ordnance Datum (aOD). The high ground acts as a watershed between the River Coquet and the River Rede , which...the River Coquet or southwards towards the River Rede . Alongside military training, the land is utilised primarily for sheep farming (cows are also

  14. Setting Priorities in the Age of Austerity: British, French, and German Experiences

    DTIC Science & Technology

    2013-01-01

    social .54 In an editorial in the French military publication, Doctrine, for example, Desportes argues that all military operations need to be regarded...German Ministry of Defense, 2007, pp. 73–74. 81 Bruno Kasdorf, “Einsatz, Doktrin und Ausbildung: Auszüge aus der Rede Generalleutnant Bruno Kasdorf...aus der Rede Generalleutnant Bruno Kasdorf Anlässlich Info-Lunch FKH Am 9, June 2011,” InfoBrief Heer, Vol. 16, No. 3, 2011

  15. The Impacts of Social Media on Citizen Security Behavior in Mexico

    DTIC Science & Technology

    2012-03-01

    Feed%3A+AnonymousIberoam erica+%28Anonymous+Iberoam%C3%A9rica%29. 188 “Propone diputado perredista regular contenido de redes sociales en Internet...citizensecurity/mexico/mexico_e.html. “Propone diputado perredista regular contenido de redes sociales en Internet.” Milenio Newspaper. Mexico City... SOCIAL MEDIA ON CITIZEN SECURITY BEHAVIOR IN MEXICO by Scott Childers March 2012 Thesis Co-Advisors: Andrew Singer Rodrigo Nieto-Gomez

  16. The Lost Path: Regulating Transit Illegal Immigration on Mexico’s Southern Border

    DTIC Science & Technology

    2014-12-01

    Protecting Immigrant Rights in Mexico,, 116. 459 María da Gloria Marroni, “Capital Social , Redes Migratorias y Ayuda Humanitaria: ¿La Solidaridad a...International and Inter-Agency Cooperation at the Border.” Geneva, Switzerland, March 13–15 (2009). Marroni, María da Gloria. “Capital Social , Redes ...32  2.  Social Networks

  17. Walker River Paiutes: A Tribal History.

    ERIC Educational Resources Information Center

    Johnson, Edward C.

    The Northern Paiute people of Nevada's Walker Lake area were known as the Agai Diccutta (Trout Eaters); they called themselves the Numa, or the People. For as long as anyone could recall, they had lived in the area, catching the huge trout from the lake and harvesting the pinon nuts and other foods from the surrounding desert. In the 1820's the…

  18. Affinity-aware checkpoint restart

    DOE PAGES

    Saini, Ajay; Rezaei, Arash; Mueller, Frank; ...

    2014-12-08

    Current checkpointing techniques employed to overcome faults for HPC applications result in inferior application performance after restart from a checkpoint for a number of applications. This is due to a lack of page and core affinity awareness of the checkpoint/restart (C/R) mechanism, i.e., application tasks originally pinned to cores may be restarted on different cores, and in case of non-uniform memory architectures (NUMA), quite common today, memory pages associated with tasks on a NUMA node may be associated with a different NUMA node after restart. Here, this work contributes a novel design technique for C/R mechanisms to preserve task-to-core mapsmore » and NUMA node specific page affinities across restarts. Experimental results with BLCR, a C/R mechanism, enhanced with affinity awareness demonstrate significant performance benefits of 37%-73% for the NAS Parallel Benchmark codes and 6-12% for NAMD with negligible overheads instead of up to nearly four times longer an execution times without affinity-aware restarts on 16 cores.« less

  19. Electro-centers control conveyors

    SciTech Connect

    Adams, K.L.; Brewer, B.K.; Kovach, J.; Brown, M.

    1981-06-01

    A suitable conveyor drive and control system has been developed for the shiftable conveyor systems at Arch Mineral Corp's Captain coal mine in southern Illinois, USA. It comprises of Westinghouse electrocenters and Numa-Logic solid state control, plus wound rotor motors for the higher horsepower and squirrel cage motors for lower horsepower applications.

  20. Walker River Paiutes: A Tribal History.

    ERIC Educational Resources Information Center

    Johnson, Edward C.

    The Northern Paiute people of Nevada's Walker Lake area were known as the Agai Diccutta (Trout Eaters); they called themselves the Numa, or the People. For as long as anyone could recall, they had lived in the area, catching the huge trout from the lake and harvesting the pinon nuts and other foods from the surrounding desert. In the 1820's the…

  1. Affinity-aware checkpoint restart

    SciTech Connect

    Saini, Ajay; Rezaei, Arash; Mueller, Frank; Hargrove, Paul; Roman, Eric

    2014-12-08

    Current checkpointing techniques employed to overcome faults for HPC applications result in inferior application performance after restart from a checkpoint for a number of applications. This is due to a lack of page and core affinity awareness of the checkpoint/restart (C/R) mechanism, i.e., application tasks originally pinned to cores may be restarted on different cores, and in case of non-uniform memory architectures (NUMA), quite common today, memory pages associated with tasks on a NUMA node may be associated with a different NUMA node after restart. Here, this work contributes a novel design technique for C/R mechanisms to preserve task-to-core maps and NUMA node specific page affinities across restarts. Experimental results with BLCR, a C/R mechanism, enhanced with affinity awareness demonstrate significant performance benefits of 37%-73% for the NAS Parallel Benchmark codes and 6-12% for NAMD with negligible overheads instead of up to nearly four times longer an execution times without affinity-aware restarts on 16 cores.

  2. Opposing motor activities are required for the organization of the mammalian mitotic spindle pole

    PubMed Central

    1996-01-01

    We use both in vitro and in vivo approaches to examine the roles of Eg5 (kinesin-related protein), cytoplasmic dynein, and dynactin in the organization of the microtubules and the localization of NuMA (Nu-clear protein that associates with the Mitotic Apparatus) at the polar ends of the mammalian mitotic spindle. Perturbation of the function of Eg5 through either immunodepletion from a cell free system for assembly of mitotic asters or antibody microinjection into cultured cells leads to organized astral microtubule arrays with expanded polar regions in which the minus ends of the microtubules emanate from a ring-like structure that contains NuMA. Conversely, perturbation of the function of cytoplasmic dynein or dynactin through either specific immunodepletition from the cell free system or expression of a dominant negative subunit of dynactin in cultured cells results in the complete lack of organization of microtubules and the failure to efficiently concentrate the NuMA protein despite its association with the microtubules. Simultaneous immunodepletion of these proteins from the cell free system for mitotic aster assembly indicates that the plus end- directed activity of Eg5 antagonizes the minus end-directed activity of cytoplasmic dynein and a minus end-directed activity associated with NuMA during the organization of the microtubules into a morphologic pole. Taken together, these results demonstrate that the unique organization of the minus ends of microtubules and the localization of NuMA at the polar ends of the mammalian mitotic spindle can be accomplished in a centrosome-independent manner by the opposing activities of plus end- and minus end-directed motors. PMID:8896597

  3. The Functionality Appreciation Scale (FAS): Development and psychometric evaluation in U.S. community women and men.

    PubMed

    Alleva, Jessica M; Tylka, Tracy L; Kroon Van Diest, Ashley M

    2017-08-17

    Body functionality has been identified as an important dimension of body image that has the potential to be useful in the prevention and treatment of negative body image and in the enhancement of positive body image. Specifically, cultivating appreciation of body functionality may offset appearance concerns. However, a scale assessing this construct has yet to be developed. Therefore, we developed the Functionality Appreciation Scale (FAS) and examined its psychometric properties among three online community samples totalling 1042 women and men (ns=490 and 552, respectively). Exploratory factor analyses revealed a unidimensional structure with seven items. Confirmatory factor analysis upheld its unidimensionality and invariance across gender. The internal consistency, test-retest reliability, criterion-related, and construct (convergent, discriminant, incremental) validity of its scores were upheld. The FAS is a psychometrically sound measure that is unique from existing positive body image measures. Scholars will find the FAS applicable within research and clinical settings. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. The motivation of stereotypic and repetitive behavior: examination of construct validity of the motivation assessment scale.

    PubMed

    Joosten, Annette V; Bundy, Anita C

    2008-08-01

    Construct validity of the Motivation Assessment Scale (MAS) (Durand, Crimmins, The Motivation Assessment Scale 1988) was studied using Rasch analysis data from 67 children (246 MASs), with dual diagnosis of autism and intellectual disability or with intellectual disability only. Results failed to support the proposed unidimensional construct or the original 4-factor structure. Some motivators appear to form a unidimensional construct: "to gain attention", "to gain a tangible object", and "to escape". There was evidence that sensory stimulation represents a different construct. Children with intellectual disability were more apt to be motivated by desire to gain a tangible item or attention. Children with the dual diagnoses were more apt to have sensory stimulation or escape from task demand as a motivator for stereotypic and repetitive behavior.

  5. Transport on a lattice with dynamical defects.

    PubMed

    Turci, Francesco; Parmeggiani, Andrea; Pitard, Estelle; Romano, M Carmen; Ciandrini, Luca

    2013-01-01

    Many transport processes in nature take place on substrates, often considered as unidimensional lanes. These unidimensional substrates are typically nonstatic: Affected by a fluctuating environment, they can undergo conformational changes. This is particularly true in biological cells, where the state of the substrate is often coupled to the active motion of macromolecular complexes, such as motor proteins on microtubules or ribosomes on mRNAs, causing new interesting phenomena. Inspired by biological processes such as protein synthesis by ribosomes and motor protein transport, we introduce the concept of localized dynamical sites coupled to a driven lattice gas dynamics. We investigate the phenomenology of transport in the presence of dynamical defects and find a regime characterized by an intermittent current and subject to severe finite-size effects. Our results demonstrate the impact of the regulatory role of the dynamical defects in transport not only in biology but also in more general contexts.

  6. The dimensionality of defense-mechanism parcels in the Defense Style Questionnaire-40.

    PubMed

    Wilkinson, Wayne W; Ritchie, Timothy D

    2015-03-01

    The Defense Style Questionnaire-40 (DSQ-40; Andrews, Singh, & Bond, 1993) uses pairs of items to measure 20 individual defense mechanisms. In a statistical sense, these item pairs represent parcels and are subject to the standards of unidimensionality demanded of parcels in general. Using a 2-facet modeling approach (N = 672), the present study examined the dimensionality of the defense-mechanism parcels in the DSQ-40 and found that the majority of the parcels did not satisfy the criteria for unidimensionality. In addition, the original 3-factor model of defense styles was not tenable with the present data. Overall, the results suggest caution when attempting to assess individual defense mechanisms using the DSQ-40. 2015 APA, all rights reserved

  7. Evaluating the Psychometric Properties of a Clinical Vocational Rehabilitation Outcome Measurement: The Assessment of Work Performance (AWP).

    PubMed

    Fan, Chia-Wei; Taylor, Renée R; Ekbladh, Elin; Hemmingsson, Helena; Sandqvist, Jan

    2013-01-01

    This study examined the validity and reliability of the Assessment of Work Performance (AWP) using Rasch analysis. The AWP was administered to 365 clients with a variety of work-related problems. Rasch analysis and principal component analysis were used to examine the appropriateness of the rating scales and unidimensionality of AWP items. The person-response validity, internal consistency, targeting appropriateness, and differential item function were also analyzed. The Rasch analysis confirmed the 4-point rating scale, and the item set met the criteria of unidimensionality. The AWP exhibited satisfactory person-response validity and internal consistency. Among the three subdomains, the targeting of item-difficulty was sufficient in the motor skills and process skills subdomains. Differential item functioning was found across gender and diagnoses. This study presented evidence to support that the AWP functioned as a reliable and valid assessment in assessing work performance. [OTJR: Occupation, Participation and Health 2013;33(3):125-133.].

  8. Testing the multidimensionality of the inventory of school motivation in a Dutch student sample.

    PubMed

    Korpershoek, Hanke; Xu, Kun; Mok, Magdalena Mo Ching; McInerney, Dennis M; van der Werf, Greetje

    2015-01-01

    A factor analytic and a Rasch measurement approach were applied to evaluate the multidimensional nature of the school motivation construct among more than 7,000 Dutch secondary school students. The Inventory of School Motivation (McInerney and Ali, 2006) was used, which intends to measure four motivation dimensions (mastery, performance, social, and extrinsic motivation), each comprising of two first-order factors. One unidimensional model and three multidimensional models (4-factor, 8-factor, higher order) were fit to the data. Results of both approaches showed that the multidimensional models validly represented the school motivation among Dutch secondary school pupils, whereas model fit of the unidimensional model was poor. The differences in model fit between the three multidimensional models were small, although a different model was favoured by the two approaches. The need for improvement of some of the items and the need to increase measurement precision of several first-order factors are discussed.

  9. Constructing one scale to describe two statewide exams.

    PubMed

    Paek, Insu; Peres, Deborah G; Wilson, Mark

    2009-01-01

    This study applies two approaches in creating a single scale from two separate statewide exams (Golden State Math Exam and California Standard Math Test) and compares some aspects of the two statewide tests. The first analysis involves a sequence of unidimensional Rasch scalings, using anchored items to scale the two tests together. The second analysis employs a 2-dimensional Rasch scaling using previous unidimensional analysis results to link the scales. The linking facilitates the investigation of their measurement properties of the two exams and is a basis for combining items from both exams to develop a more efficient testing program. The results of the comparisons of the two statewide exams based on the linking are shown and discussed.

  10. Absolute magnitude estimation and relative judgement approaches to subjective workload assessment

    NASA Technical Reports Server (NTRS)

    Vidulich, Michael A.; Tsang, Pamela S.

    1987-01-01

    Two rating scale techniques employing an absolute magnitude estimation method, were compared to a relative judgment method for assessing subjective workload. One of the absolute estimation techniques used was an unidimensional overall workload scale and the other was the multidimensional NASA-Task Load Index technique. Thomas Saaty's Analytic Hierarchy Process was the unidimensional relative judgment method used. These techniques were used to assess the subjective workload of various single- and dual-tracking conditions. The validity of the techniques was defined as their ability to detect the same phenomena observed in the tracking performance. Reliability was assessed by calculating test-retest correlations. Within the context of the experiment, the Saaty Analytic Hierarchy Process was found to be superior in validity and reliability. These findings suggest that the relative judgment method would be an effective addition to the currently available subjective workload assessment techniques.

  11. Properties of the Tampa Scale for Kinesiophobia across Workers with Different Pain Experiences and Cultural Backgrounds: A Rasch Analysis.

    PubMed

    Jørgensen, M B; Damsgård, E; Holtermann, A; Anke, A; Søgaard, K; Røe, C

    2015-01-01

    The main aim of this study was to evaluate whether the construct validity of the Tampa Scale for Kinesiophobia (TSK) is consistent with respect to its scaling properties, unidimensionality and targeting among workers with different levels of pain. The 311 participating Danish workers reported kinesiophobia by TSK (13 statement version) and number of days with pain during the past year (less than 8 days, less than 90 days and greater than 90 days). A Rasch analysis was used to evaluate the measurement properties of the TSK in the workers across pain levels, ages, genders and ethnicities. The TSK did not fit the Rasch model, but removing one item solved the poorness of fit. Invariance was found across the pain levels, ages and genders. Thus, with a few modifications, the TSK was shown to capture a unidimensional construct of fear of movement in workers with different pain levels, ages, and genders.

  12. Transport on a lattice with dynamical defects

    NASA Astrophysics Data System (ADS)

    Turci, Francesco; Parmeggiani, Andrea; Pitard, Estelle; Romano, M. Carmen; Ciandrini, Luca

    2013-01-01

    Many transport processes in nature take place on substrates, often considered as unidimensional lanes. These unidimensional substrates are typically nonstatic: Affected by a fluctuating environment, they can undergo conformational changes. This is particularly true in biological cells, where the state of the substrate is often coupled to the active motion of macromolecular complexes, such as motor proteins on microtubules or ribosomes on mRNAs, causing new interesting phenomena. Inspired by biological processes such as protein synthesis by ribosomes and motor protein transport, we introduce the concept of localized dynamical sites coupled to a driven lattice gas dynamics. We investigate the phenomenology of transport in the presence of dynamical defects and find a regime characterized by an intermittent current and subject to severe finite-size effects. Our results demonstrate the impact of the regulatory role of the dynamical defects in transport not only in biology but also in more general contexts.

  13. Re-Estimation of Student Ability in Foreign Languages Using the Rasch Model

    DTIC Science & Technology

    1988-01-01

    assumed by evaluators that examinee scores on a valid test are reasonable by virtue of high reliability (usually measured by Kuder - Richardson 20) without...both subtests (split-half reliability ). If the domain sampling model (unidimensional) is in view, then the Kuder - Richardson (KR) formulae are more...separation reliability is a maximum-likelihood equivalent to the Kuder - Richardson -20 or Cronbach’s Coefficient Alpha reliability indices. This internal

  14. Construct continuity in the presence of multidimensionality

    NASA Astrophysics Data System (ADS)

    Staniewska, Dorota

    Unidimensionality -- a condition, under which only one dominant construct is being measured by the test, is a fundamental assumption of most modern day psychometric models. However, some tests are multidimensional by design. A test, for instance, might measure physics, biology and chemistry subscales combined to measure a "general science" composite. The relative magnitudes of those subscales sometimes shift from administration to administration, which results in an altered composite. This study examined the conditions under which two different forms of a multidimensional test measure the same composite construct to a degree that allows them to be equated, i.e. used interchangeably. IRT true-score equating was used in a simulation study to assess the closeness of the scores on the forms. Conditions examined included the correlations between subscales, varying number of items per subscale form to form, and different subpopulation ability estimates on the subscales. Differences in the equating errors due to generating model (1PL or 3PL) were also examined. A way of calculating a unidimensional composite from a two-dimensional ability was devised and compared to the unidimensional composite obtained from Parscale. It was found that in general, the errors increase with decreasing correlation between traits and increased divergence of the two forms to be equated, with the later being the main predictor of the equating errors. However, the magnitude of those errors was small for the population as a whole especially when all examinee abilities are drawn from the same distribution. It was concluded that IRT true score equating is relatively robust to multidimensionality for the conditions examined, especially if the overall population score is desired. However, when accurate estimate of the equated score for individuals at the extremes of the population is needed, or whenever population abilities are drawn from more than one distribution, the unidimensional true score

  15. Relative Difficulties of Daily Living Tasks with Retinitis Pigmentosa.

    PubMed

    Latham, Keziah; Baranian, Mohammad; Timmis, Matthew A; Fisher, Andy; Pardhan, Shahina

    2017-03-01

    To determine the relative difficulty of activity of daily living tasks for people with retinitis pigmentosa (RP). Participants with RP (n = 166) rated the difficulty of tasks (n = 43) underpinning the Dutch Activity Inventory goals of mobility indoors and outdoors, shopping, and using public transport. Demographic characteristics were also determined. Responses were Rasch analyzed to determine properties of the scale, derive unidimensional subscales, and consider differential item functioning (DIF). After removal of one ill-fitting item, the remaining 42 tasks formed a scale with reasonable Rasch parameters but poor unidimensionality. The most difficult tasks were orienting in poor and bright light both indoors and outdoors, and avoiding peripheral obstacles outdoors. Eight subscales were derived with unidimensional properties, each of which could be considered as requiring similar skills. DIF identified that tasks from the "poor light and obstacles" subscale were more difficult for those younger than the median age, nonusers of mobility aids, and those not registered or registered sight impaired. Tasks from the "finding products" and "public transport" subscales were more difficult for those older than the median age, with longer duration of visual loss, users of mobility aids, and those registered severely sight impaired. The most difficult tasks for people with RP of orienting in poor light and avoiding peripheral obstacles are relatively more difficult for those not registered as "severely sight impaired," but are less difficult for those who use mobility aids. Mobility aids (guide dog or cane), therefore, do benefit users in their perceived ability in these particular tasks. The derived unidimensional subscales reorganize the tasks from those grouped together by goal (researcher driven) to those perceived as requiring similar skills by people with RP (patient driven) and can be used as an evidence base for orientation and mobility training protocols.

  16. Rasch analysis of the Chedoke-McMaster Attitudes towards Children with Handicaps scale.

    PubMed

    Armstrong, Megan; Morris, Christopher; Tarrant, Mark; Abraham, Charles; Horton, Mike C

    2017-02-01

    Aim To assess whether the Chedoke-McMaster Attitudes towards Children with Handicaps (CATCH) 36-item total scale and subscales fit the unidimensional Rasch model. Method The CATCH was administered to 1881 children, aged 7-16 years in a cross-sectional survey. Data were used from a random sample of 416 for the initial Rasch analysis. The analysis was performed on the 36-item scale and then separately for each subscale. The analysis explored fit to the Rasch model in terms of overall scale fit, individual item fit, item response categories, and unidimensionality. Item bias for gender and school level was also assessed. Revised scales were then tested on an independent second random sample of 415 children. Results Analyses indicated that the 36-item overall scale was not unidimensional and did not fit the Rasch model. Two scales of affective attitudes and behavioural intention were retained after four items were removed from each due to misfit to the Rasch model. Additionally, the scaling was improved when the two most negative response categories were aggregated. There was no item bias by gender or school level on the revised scales. Items assessing cognitive attitudes did not fit the Rasch model and had low internal consistency as a scale. Conclusion Affective attitudes and behavioural intention CATCH sub-scales should be treated separately. Caution should be exercised when using the cognitive subscale. Implications for Rehabilitation The 36-item Chedoke-McMaster Attitudes towards Children with Handicaps (CATCH) scale as a whole did not fit the Rasch model; thus indicating a multi-dimensional scale. Researchers should use two revised eight-item subscales of affective attitudes and behavioural intentions when exploring interventions aiming to improve children's attitudes towards disabled people or factors associated with those attitudes. Researchers should use the cognitive subscale with caution, as it did not create a unidimensional and internally consistent scale

  17. Rasch analysis of the Western Ontario MacMaster questionnaire (WOMAC) in 2205 patients with osteoarthritis, rheumatoid arthritis, and fibromyalgia.

    PubMed

    Wolfe, F; Kong, S X

    1999-09-01

    Advances in health measurement have led to the application of Rasch Item Response Theory (IRT) analysis (Rasch analysis) to evaluate instruments measuring health status and quality of life of patients, including the Health Assessment Questionnaire and SF-36. This study investigated the extent to which the Western Ontario MacMaster osteoarthritis questionnaire (WOMAC) satisfies the Rasch model, particularly in respect to unidimensionality, item separation, and linearity. The study included a total of 2205 patients, 1013 with rheumatoid arthritis (RA), 655 with osteoarthritis of the knee or hip (OA), and 537 with fibromyalgia. All patients completed the WOMAC as part of a longitudinal study of rheumatic disease outcomes. To examine whether the WOMAC pain and function scales each fits the Rasch model, the Winsteps program was used to assess item difficulty, scale unidimensionality, item separation, and linearity. Although the WOMAC worked best in OA, regardless of disorder, both the pain and function scales were unidimensional, had adequate item separation, and had a long range (25-150) of linearity in the function scale. Several functional items, however, had a high information weight fit (INFIT) statistic, indicating poor fit to the model. These items included "getting in and out of the bath" and "going down stairs." The WOMAC generally satisfies the requirements of Rasch item response theory across all disorders studied, and is an appropriate measure of lower body function in OA, RA and fibromyalgia. Although some individual items do not fit well, it is not likely that removing such items would result in more than overall minimal differences, and it will be difficult to remove traces of multidimensionality while keeping the central constructs of progressive lower body musculoskeletal abnormality intact. In addition, it is possible that a "purer", still more unidimensional instrument would be less useful in clinical trials and epidemiological studies by restricting

  18. Rasch analysis of the Western Ontario MacMaster Questionnaire (WOMAC) in 2205 patients with osteoarthritis, rheumatoid arthritis, and fibromyalgia

    PubMed Central

    Wolfe, F.; Kong, S.

    1999-01-01

    OBJECTIVE—Advances in health measurement have led to the application of Rasch Item Response Theory (IRT) analysis (Rasch analysis) to evaluate instruments measuring health status and quality of life of patients, including the Health Assessment Questionnaire and SF-36. This study investigated the extent to which the Western Ontario MacMaster osteoarthritis questionnaire (WOMAC) satisfies the Rasch model, particularly in respect to unidimensionality, item separation, and linearity.
METHODS—The study included a total of 2205 patients, 1013 with rheumatoid arthritis (RA), 655 with osteoarthritis of the knee or hip (OA), and 537 with fibromyalgia. All patients completed the WOMAC as part of a longitudinal study of rheumatic disease outcomes. To examine whether the WOMAC pain and function scales each fits the Rasch model, the Winsteps program was used to assess item difficulty, scale unidimensionality, item separation, and linearity.
RESULTS—Although the WOMAC worked best in OA, regardless of disorder, both the pain and function scales were unidimensional, had adequate item separation, and had a long range (25-150) of linearity in the function scale. Several functional items, however, had a high information weight fit (INFIT) statistic, indicating poor fit to the model. These items included "getting in and out of the bath" and "going down stairs."
CONCLUSION—The WOMAC generally satisfies the requirements of Rasch item response theory across all disorders studied, and is an appropriate measure of lower body function in OA, RA and fibromyalgia. Although some individual items do not fit well, it is not likely that removing such items would result in more than overall minimal differences, and it will be difficult to remove traces of multidimensionality while keeping the central constructs of progressive lower body musculoskeletal abnormality intact. In addition, it is possible that a "purer", still more unidimensional instrument would be less useful in

  19. Models and Estimation Procedures for the Analysis of Subjects-by-Items Data Arrays.

    DTIC Science & Technology

    1982-06-30

    dichotomous , Tukey’s model may or may not be competitive with Rasch models and other logistic models . Whether it is or not...Tukey’s model is worth considering as an alternative to Rasch models as a basis for scaling unidimensional latent traits. If one adopts Tukey’s model ...which is the foundation of Rasch’s (1959) Poisson and gamma models . Rasch’s model for analysis of dichotomous items has the same

  20. A Monte Carlo Study of Item Bias Detection in Multidimensional Tests.

    DTIC Science & Technology

    1984-08-20

    models are the one parameter model ( Rasch , 1960; Wright, 1977) or the two parameter logistic model (Lord and Novick, 1968). Choosing among the models ...related across groups this may be due to a lack of model fit rather than bias. For example , a violation of unidimensionality assumption could be detected...is necessary to adequately model dichotomously scored item responses. The coumon factor model represents continuous observed variables, x, as