Are fit indices really fit to estimate the number of factors with categorical variables?: some cautionary findings via Monte Carlo Simulation

This paper is not the copy of record and may not exactly replicate the authoritative document published in the APA journal. Please do not copy or cite without author's permission. The final article is available, upon publication, at: http://dx.doi.org/10.1037/met0000064An early step in the process of construct validation consists of establishing the fit of an unrestricted "exploratory" factorial model for a prespecified number of common factors. For this initial unrestricted model, researchers have often recommended and used fit indices to estimate the number of factors to retain. Despite the logical appeal of this approach, little is known about the actual accuracy of fit indices in the estimation of data dimensionality. The present study aimed to reduce this gap by systematically evaluating the performance of 4 commonly used fit indices-the comparative fit index (CFI), the Tucker-Lewis index (TLI), the root mean square error of approximation (RMSEA), and the standardized root mean square residual (SRMR)-in the estimation of the number of factors with categorical variables, and comparing it with what is arguably the current golden rule, Horn's (1965) parallel analysis. The results indicate that the CFI and TLI provide nearly identical estimations and are the most accurate fit indices, followed at a step below by the RMSEA, and then by the SRMR, which gives notably poor dimensionality estimates. Difficulties in establishing optimal cutoff values for the fit indices and the general superiority of parallel analysis, however, suggest that applied researchers are better served by complementing their theoretical considerations regarding dimensionality with the estimates provided by the latter metho

Searching for G: A New evaluation of SPM-LS dimensionality

There has been increased interest in assessing the quality and usefulness of short versions of the Raven’s Progressive Matrices. A recent proposal, composed of the last twelve matrices of the Standard Progressive Matrices (SPM-LS), has been depicted as a valid measure of g. Nonetheless, the results provided in the initial validation questioned the assumption of essential unidimensionality for SPM-LS scores. We tested this hypothesis through two di erent statistical techniques. Firstly, we applied exploratory graph analysis to assess SPM-LS dimensionality. Secondly, exploratory bi-factor modelling was employed to understand the extent that potential specific factors represent significant sources of variance after a general factor has been considered. Results evidenced that if modelled appropriately, SPM-LS scores are essentially unidimensional, and that constitute a reliable measure of g. However, an additional specific factor was systematically identified for the last six items of the test. The implications of such findings for future work on the SPM-LS are discusse

An Unexpected Access to a New Sphingoid Base Containing a Vinyl Sulfide Unit

An unexpected access to a new sphingoid base containing a vinyl sulfide unit is described. The process involves the ‘one-pot' regioselective opening of an epoxide with a thiolate, followed by intramolecular acyl transfer, base-promoted elimination, and final hydrolysis. Excess sodium hydride and high dilution conditions are required for optimal yields. The process is amenable to a variety of thiolates. The resulting compounds can be regarded as new hybrid sphingoid bases that combine some structural motifs present in other reported sphingolipid analogues.Peer reviewe

Bi-factor exploratory structural equation modeling done right: using the SLiDapp application

Background: Due to its fl exibility and statistical properties, bi-factor Exploratory Structural Equation Modeling (bi-factor ESEM) has become an often-recommended tool in psychometrics. Unfortunately, most recent methods for approximating these structures, such as the SLiD algorithm, are not available in the leading software for performing ESEM (i.e., Mplus). To resolve this issue, we present a novel, user-friendly Shiny application for integrating the SLiD algorithm in bi-factor ESEM estimation in Mplus. Thus, a two-stage framework for conducting SLiDbased bi-factor ESEM in Mplus was developed. Method: This approach was presented in a step-by-step guide for applied researchers, showing the utility of the developed SLiDApp application. Using data from the Open-Source Psychometrics Project (N = 2495), we conducted a bi-factor ESEM exploration of the Generic Conspiracist Beliefs Scale. We studied whether bi-factor modelling was appropriate and if both general and group factors were related to each personality trait. Results: The application of the SLiD algorithm provided unique information regarding this factor structure and its ESEM structural parameters. Conclusions: The results illustrated the usefulness and validity of SLiD-based bi-factor ESEM, and how the proposed Shiny app could make it eaiser for applied researchers to use these methodsThis work was supported by Grant FPU15/ 03246 from the Ministry of Education, Culture and Sports (Spain), by the Cátedra de Modelos y Aplicaciones Psicométricos (Instituto de Ingeniería del Conocimiento and Autonomous University of Madrid) and by Grant PSI2017-85022-P from Ministerio de Economia y Competitividad (Spain) and Fondo Social Europe

Análisis y cálculo de la estructura de una plataforma elevadora móvil de personal (PEMP)

En el siguiente trabajo de fin de grado se abordara el análisis y cálculo de la estructura de elevación de una plataforma elevadora móvil de personal (PEMP) para diferentes cargas y posiciones de estas, combinadas con distintas posibilidades de elevación. Para la realización del trabajo se van a usar una serie de herramientas informática de diseño asistido por ordenador, en este caso "AutoCAD 2016" para diseño en 2D y "SolidWorks 2016" para diseño tridimensional, así como herramientas matemáticas como el programa "EES (Engineering Equation Solver)" para la resolución de las múltiples ecuaciones que se afrontaran a lo largo del proyecto. Además nos apoyaremos en hojas de cálculo mediante el software "Excel" de Microsoft Office. Dicho trabajo consta de una memoria resumen, en la que se presenta el objetivo del proyecto y se expone un resumen de los anexos, y de tres anexos en los cuales se expondrá de manera extensa todo el trabajo realizado

Metastatic non-muscle invasive bladder cancer with cervical lymph node metastasis.

Bladder cancer is a common cancer that may present as superfi cial, invasive, or metastatic disease. Non‐muscle‐invasive bladder cancer (NMIBC) represents the majority of bladder cancer diagnoses, but represents a spectrum of disease with a variable clinical course, notably for signifi cant risk of recurrence and potential for progression. NMIBC metastasis to distant organs without local invasion or regional metastasis is a very rare occurrence, so there are limited case reports about early metastasis in the literature.post-print4,59 M

Effect of various dietary regimens on oral challenge with Mycobacterium avium subsp. paratuberculosis in a rabbit model

Rabbits are susceptible to infection by Mycobacterium avium subspecies paratuberculosis (MAP) in both wildlife and experimental conditions. Under the hypotheses that nutrient balance might influence the establishment of infection, we designed an experiment where MAP intestinal colonization was assessed under three dietary regimens: high fiber, high protein, and regular diet in New Zealand white rabbits submitted to oral challenge with MAP.Lowest weight gain (F=5.17, p=0.024), higher tissue culture positivity rates (X2=7.43, p=0.024) and especially extended MAP-compatible lesions (F=5.78, p=0.017) were detected in the regular diet.Taken altogether, results indicate that paratuberculosis infection was achieved affecting mostly regular diet animals and showing that dietary changes may modulate the course of the infection

Obstructive uropathy secondary to ureteral inguinoscrotal hernia.

post-print2,18 M

Nuevo banco de ítems para evaluar adaptativamente los Cinco Grandes

Even though the Five Factor Model (FFM) has been the dominant paradigm in personality research for the past two decades, very few studies have measured the FFM adaptively. Thus, the purpose of this research was the building of a new item pool to develop a computerized adaptive test (CAT) for personality assessment. Method: A pool of 480 items that measured the FFM facets was developed and applied to 826 participants. Facets were calibrated separately and item selection was performed being mindful of the preservation of unidimensionality of each facet. Then, a post-hoc simulation study was carried out to test the performance of separate CATs to measure the facets. Results: The final item pool was composed of 360 items with good psychometric properties. Findings reveal that a CAT administration of four items per facet (total length of 120 items) provides accurate facets scores, while maintaining the factor structure of the FFM. Conclusions: An item pool with good psychometric properties was obtained and a CAT simulation study demonstrated that the FFM facets could be measured with precision using a third of the items in the poolA pesar de que el Modelo de los Cinco Factores (MCF) ha sido el paradigma predominante durante las últimas dos décadas, muy pocos estudios han medido el MCF de forma adaptativa. El objetivo de esta investigación fue construir un nuevo banco de ítems para desarrollar un test adaptativo informatizado (TAI) para evaluar la personalidad. Método: se desarrolló un banco de 480 ítems para evaluar las facetas del MCF y se aplicó a 826 participantes. Cada faceta se calibró por separado y la selección de ítems se realizó atendiendo a que cada faceta fuese unidimensional. Después se realizó un estudio de simulación post-hoc para evaluar la efi ciencia de TAIs a nivel de facetas. Resultados: el banco final estaba formado por 360 ítems con buenas propiedades psicométricas. Los resultados demostraron que la aplicación adaptativa de cuatro ítems por faceta proporciona puntuaciones precisas en las mismas, al mismo tiempo que se mantiene la estructura factorial del MCF. Conclusiones: el banco final está formado por ítems con buenas propiedades psicométricas. La aplicación adaptativa del banco permite medir la personalidad de forma eficiente a nivel de facetas utilizando una tercera parte de los ítemsThe research has been funded by the Ministry of Economy and Competitivity of Spain (PSI2013-44300-P), and the UAM-IIC Chair «Psychometric Models and Applications

Laboratory and telescope demonstration of the TP3-WFS for the adaptive optics segment of AOLI

AOLI (Adaptive Optics Lucky Imager) is a state-of-art instrument that combines adaptive optics (AO) and lucky imaging (LI) with the objective of obtaining diffraction limited images in visible wavelength at mid- and big-size ground-based telescopes. The key innovation of AOLI is the development and use of the new TP3-WFS (Two Pupil Plane PositionsWavefront Sensor). The TP3-WFS, working in visible band, represents an advance over classical wavefront sensors such as the Shack-Hartmann WFS (SH-WFS) because it can theoretically use fainter natural reference stars, which would ultimately provide better sky coverages to AO instruments using this newer sensor. This paper describes the software, algorithms and procedures that enabled AOLI to become the first astronomical instrument performing real-time adaptive optics corrections in a telescope with this new type of WFS, including the first control-related results at the William Herschel Telescope (WHT)This work was supported by the Spanish Ministry of Economy under the projects AYA2011-29024, ESP2014-56869-C2-2-P, ESP2015-69020-C2-2-R and DPI2015-66458-C2-2-R, by project 15345/PI/10 from the Fundación Séneca, by the Spanish Ministry of Education under the grant FPU12/05573, by project ST/K002368/1 from the Science and Technology Facilities Council and by ERDF funds from the European Commission. The results presented in this paper are based on observations made with the William Herschel Telescope operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. Special thanks go to Lara Monteagudo and Marcos Pellejero for their timely contributions